<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.fortinet.com/role/AccumulatedOtherComprehensiveLoss" xlink:href="ftnt-20190331.xsd#AccumulatedOtherComprehensiveLoss" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/AccumulatedOtherComprehensiveLossChangesInAccumulatedBalancesOfOtherComprehensiveLossDetails" xlink:href="ftnt-20190331.xsd#AccumulatedOtherComprehensiveLossChangesInAccumulatedBalancesOfOtherComprehensiveLossDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/AccumulatedOtherComprehensiveLossTables" xlink:href="ftnt-20190331.xsd#AccumulatedOtherComprehensiveLossTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/BusinessCombination" xlink:href="ftnt-20190331.xsd#BusinessCombination" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/BusinessCombinationAdditionalInformationDetails" xlink:href="ftnt-20190331.xsd#BusinessCombinationAdditionalInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/CommitmentsAndContingencies" xlink:href="ftnt-20190331.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/CommitmentsAndContingenciesDetails" xlink:href="ftnt-20190331.xsd#CommitmentsAndContingenciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/CommitmentsAndContingenciesMinimumOperatingLeasePaymentsDetails" xlink:href="ftnt-20190331.xsd#CommitmentsAndContingenciesMinimumOperatingLeasePaymentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/CommitmentsAndContingenciesTables" xlink:href="ftnt-20190331.xsd#CommitmentsAndContingenciesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/ConsolidatedBalanceSheets" xlink:href="ftnt-20190331.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="ftnt-20190331.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="ftnt-20190331.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:href="ftnt-20190331.xsd#ConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/ConsolidatedStatementsOfIncome" xlink:href="ftnt-20190331.xsd#ConsolidatedStatementsOfIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/ConsolidatedStatementsOfStockholdersEquity" xlink:href="ftnt-20190331.xsd#ConsolidatedStatementsOfStockholdersEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/DefinedContributionPlans" xlink:href="ftnt-20190331.xsd#DefinedContributionPlans" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/DefinedContributionPlansDetails" xlink:href="ftnt-20190331.xsd#DefinedContributionPlansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/DocumentAndEntityInformation" xlink:href="ftnt-20190331.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/FinancialInstrumentsAndFairValue" xlink:href="ftnt-20190331.xsd#FinancialInstrumentsAndFairValue" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/FinancialInstrumentsAndFairValueFairValueMeasurementsDetails" xlink:href="ftnt-20190331.xsd#FinancialInstrumentsAndFairValueFairValueMeasurementsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/FinancialInstrumentsAndFairValueInvestmentsDetails" xlink:href="ftnt-20190331.xsd#FinancialInstrumentsAndFairValueInvestmentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/FinancialInstrumentsAndFairValueTables" xlink:href="ftnt-20190331.xsd#FinancialInstrumentsAndFairValueTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/GoodwillAndOtherIntangibleAssetsNet" xlink:href="ftnt-20190331.xsd#GoodwillAndOtherIntangibleAssetsNet" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/GoodwillAndOtherIntangibleAssetsNetEstimatedFutureAmortizationExpenseDetails" xlink:href="ftnt-20190331.xsd#GoodwillAndOtherIntangibleAssetsNetEstimatedFutureAmortizationExpenseDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/GoodwillAndOtherIntangibleAssetsNetNarrativeDetails" xlink:href="ftnt-20190331.xsd#GoodwillAndOtherIntangibleAssetsNetNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/GoodwillAndOtherIntangibleAssetsNetOtherIntangibleAssetsNetDetails" xlink:href="ftnt-20190331.xsd#GoodwillAndOtherIntangibleAssetsNetOtherIntangibleAssetsNetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/GoodwillAndOtherIntangibleAssetsNetTables" xlink:href="ftnt-20190331.xsd#GoodwillAndOtherIntangibleAssetsNetTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/IncomeTaxes" xlink:href="ftnt-20190331.xsd#IncomeTaxes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/IncomeTaxesNarrativeDetails" xlink:href="ftnt-20190331.xsd#IncomeTaxesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/Inventory" xlink:href="ftnt-20190331.xsd#Inventory" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/InventoryDetails" xlink:href="ftnt-20190331.xsd#InventoryDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/InventoryTables" xlink:href="ftnt-20190331.xsd#InventoryTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/InvestmentsInPrivatelyHeldCompanies" xlink:href="ftnt-20190331.xsd#InvestmentsInPrivatelyHeldCompanies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/InvestmentsInPrivatelyHeldCompaniesDetails" xlink:href="ftnt-20190331.xsd#InvestmentsInPrivatelyHeldCompaniesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/Leases" xlink:href="ftnt-20190331.xsd#Leases" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/LeasesComponentsOfLeaseExpenseDetails" xlink:href="ftnt-20190331.xsd#LeasesComponentsOfLeaseExpenseDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/LeasesDetails" xlink:href="ftnt-20190331.xsd#LeasesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/LeasesFuturePrincipalContractualObligationsForOperatingLeaseCommitmentsDetails" xlink:href="ftnt-20190331.xsd#LeasesFuturePrincipalContractualObligationsForOperatingLeaseCommitmentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/LeasesMaturitiesOfOperatingLeaseLiabilitiesDetails" xlink:href="ftnt-20190331.xsd#LeasesMaturitiesOfOperatingLeaseLiabilitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/LeasesSupplementalBalanceSheetInformationDetails" xlink:href="ftnt-20190331.xsd#LeasesSupplementalBalanceSheetInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/LeasesSupplementalCashFlowInformationDetails" xlink:href="ftnt-20190331.xsd#LeasesSupplementalCashFlowInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/LeasesTables" xlink:href="ftnt-20190331.xsd#LeasesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/NetIncomePerShare" xlink:href="ftnt-20190331.xsd#NetIncomePerShare" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/NetIncomePerShareAntiDilutiveSecuritiesDetails" xlink:href="ftnt-20190331.xsd#NetIncomePerShareAntiDilutiveSecuritiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/NetIncomePerShareCalculationOfBasicAndDilutedDetails" xlink:href="ftnt-20190331.xsd#NetIncomePerShareCalculationOfBasicAndDilutedDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/NetIncomePerShareTables" xlink:href="ftnt-20190331.xsd#NetIncomePerShareTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/PropertyAndEquipmentnet" xlink:href="ftnt-20190331.xsd#PropertyAndEquipmentnet" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/PropertyAndEquipmentnetDetails" xlink:href="ftnt-20190331.xsd#PropertyAndEquipmentnetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/PropertyAndEquipmentnetTables" xlink:href="ftnt-20190331.xsd#PropertyAndEquipmentnetTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/RevenueRecognition" xlink:href="ftnt-20190331.xsd#RevenueRecognition" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/RevenueRecognitionDetails" xlink:href="ftnt-20190331.xsd#RevenueRecognitionDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/RevenueRecognitionDisaggregatedRevenuesDetails" xlink:href="ftnt-20190331.xsd#RevenueRecognitionDisaggregatedRevenuesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/RevenueRecognitionPerformanceObligationSatisfactionPeriodDetails" xlink:href="ftnt-20190331.xsd#RevenueRecognitionPerformanceObligationSatisfactionPeriodDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/RevenueRecognitionTables" xlink:href="ftnt-20190331.xsd#RevenueRecognitionTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/SegmentInformation" xlink:href="ftnt-20190331.xsd#SegmentInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/SegmentInformationDetails" xlink:href="ftnt-20190331.xsd#SegmentInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/SegmentInformationTables" xlink:href="ftnt-20190331.xsd#SegmentInformationTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/StockholdersEquity" xlink:href="ftnt-20190331.xsd#StockholdersEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/StockholdersEquityAllocationOfStockBasedCompensationExpenseDetails" xlink:href="ftnt-20190331.xsd#StockholdersEquityAllocationOfStockBasedCompensationExpenseDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/StockholdersEquityDetails" xlink:href="ftnt-20190331.xsd#StockholdersEquityDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/StockholdersEquityRestrictedStockUnitsActivityDetails" xlink:href="ftnt-20190331.xsd#StockholdersEquityRestrictedStockUnitsActivityDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/StockholdersEquityShareRepurchaseProgramDetails" xlink:href="ftnt-20190331.xsd#StockholdersEquityShareRepurchaseProgramDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/StockholdersEquityTables" xlink:href="ftnt-20190331.xsd#StockholdersEquityTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/SummaryOfSignificantAccountingPolicies" xlink:href="ftnt-20190331.xsd#SummaryOfSignificantAccountingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:href="ftnt-20190331.xsd#SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.fortinet.com/role/SummaryOfSignificantAccountingPoliciesRecentAccountingPronouncementsDetails" xlink:href="ftnt-20190331.xsd#SummaryOfSignificantAccountingPoliciesRecentAccountingPronouncementsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedLabel" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedNetLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedNetLabel" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedPeriodEndLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedPeriodEndLabel" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedPeriodStartLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedPeriodStartLabel" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedTerseLabel" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedTotalLabel" xlink:type="simple" />
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/netLabel" xlink:href="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd#netLabel" xlink:type="simple" />
  <link:presentationLink xlink:role="http://www.fortinet.com/role/AccumulatedOtherComprehensiveLoss" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_7820140764EB88976A826E4D05530C71" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNoteTextBlock" xlink:label="loc_us-gaap_ComprehensiveIncomeNoteTextBlock_13B35E5A5828477939946E4D055422FB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_7820140764EB88976A826E4D05530C71" xlink:to="loc_us-gaap_ComprehensiveIncomeNoteTextBlock_13B35E5A5828477939946E4D055422FB" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/AccumulatedOtherComprehensiveLossChangesInAccumulatedBalancesOfOtherComprehensiveLossDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_33F04B2BBC72751DE13774E297460D22" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_A59E6F1E9EAB1F3B6CEB74E29746627C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_33F04B2BBC72751DE13774E297460D22" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_A59E6F1E9EAB1F3B6CEB74E29746627C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_063E73C0BE66A1F775C974E297478345" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_A59E6F1E9EAB1F3B6CEB74E29746627C" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_063E73C0BE66A1F775C974E297478345" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_61B299AB07E97DC67AB774E297471473" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_063E73C0BE66A1F775C974E297478345" xlink:to="loc_us-gaap_EquityComponentDomain_61B299AB07E97DC67AB774E297471473" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_4C15590B27BE73BD478574E297476497" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_61B299AB07E97DC67AB774E297471473" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_4C15590B27BE73BD478574E297476497" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_A5DD0F177384D5DD10A374E2974884DB" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_A59E6F1E9EAB1F3B6CEB74E29746627C" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_A5DD0F177384D5DD10A374E2974884DB" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_AccumulatedOtherComprehensiveIncomeRollForward" xlink:label="loc_ftnt_AccumulatedOtherComprehensiveIncomeRollForward_DD984CAC48C722E9D36174E297487D37" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_A5DD0F177384D5DD10A374E2974884DB" xlink:to="loc_ftnt_AccumulatedOtherComprehensiveIncomeRollForward_DD984CAC48C722E9D36174E297487D37" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_E9602D6A5CB6C56E6B2E74E29748F0F9" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_AccumulatedOtherComprehensiveIncomeRollForward_DD984CAC48C722E9D36174E297487D37" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_E9602D6A5CB6C56E6B2E74E29748F0F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_5123A4734177510A42F374E29748045A" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_AccumulatedOtherComprehensiveIncomeRollForward_DD984CAC48C722E9D36174E297487D37" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_5123A4734177510A42F374E29748045A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_B2BDFA809C255EC84C6274E297499368" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_AccumulatedOtherComprehensiveIncomeRollForward_DD984CAC48C722E9D36174E297487D37" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_B2BDFA809C255EC84C6274E297499368" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_BEA872A3A113224D547074E2974979D2" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_AccumulatedOtherComprehensiveIncomeRollForward_DD984CAC48C722E9D36174E297487D37" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_BEA872A3A113224D547074E2974979D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_F078BE3409203D149DE174E2974931FB" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_AccumulatedOtherComprehensiveIncomeRollForward_DD984CAC48C722E9D36174E297487D37" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_F078BE3409203D149DE174E2974931FB" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_AccumulatedOtherComprehensiveIncomeTaxRollForward" xlink:label="loc_ftnt_AccumulatedOtherComprehensiveIncomeTaxRollForward_1D9F74C10BB6AC44C09474E2974998A8" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_A5DD0F177384D5DD10A374E2974884DB" xlink:to="loc_ftnt_AccumulatedOtherComprehensiveIncomeTaxRollForward_1D9F74C10BB6AC44C09474E2974998A8" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_AccumulatedOtherComprehensiveIncomeLossTax" xlink:label="loc_ftnt_AccumulatedOtherComprehensiveIncomeLossTax_7D8A851875E08AAFEB1D74E2974944AB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_AccumulatedOtherComprehensiveIncomeTaxRollForward_1D9F74C10BB6AC44C09474E2974998A8" xlink:to="loc_ftnt_AccumulatedOtherComprehensiveIncomeLossTax_7D8A851875E08AAFEB1D74E2974944AB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax_2234046AFFA871BF649374E2974A0E3A" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_AccumulatedOtherComprehensiveIncomeTaxRollForward_1D9F74C10BB6AC44C09474E2974998A8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax_2234046AFFA871BF649374E2974A0E3A" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ReclassificationfromAccumulatedOtherComprehensiveIncomeCurrentPeriodTax" xlink:label="loc_ftnt_ReclassificationfromAccumulatedOtherComprehensiveIncomeCurrentPeriodTax_7960DE951FEB5E120F9B74E2974A5BF0" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_AccumulatedOtherComprehensiveIncomeTaxRollForward_1D9F74C10BB6AC44C09474E2974998A8" xlink:to="loc_ftnt_ReclassificationfromAccumulatedOtherComprehensiveIncomeCurrentPeriodTax_7960DE951FEB5E120F9B74E2974A5BF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTax_F70F254B86534D5C6E9474E2974A72DC" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_AccumulatedOtherComprehensiveIncomeTaxRollForward_1D9F74C10BB6AC44C09474E2974998A8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTax_F70F254B86534D5C6E9474E2974A72DC" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_AccumulatedOtherComprehensiveIncomeLossTax" xlink:label="loc_ftnt_AccumulatedOtherComprehensiveIncomeLossTax_C7A10FC321C0A90F359774E2974AB81F" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_AccumulatedOtherComprehensiveIncomeTaxRollForward_1D9F74C10BB6AC44C09474E2974998A8" xlink:to="loc_ftnt_AccumulatedOtherComprehensiveIncomeLossTax_C7A10FC321C0A90F359774E2974AB81F" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/AccumulatedOtherComprehensiveLossTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_2D2190B31505F1D6B6416E4D03669982" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock_F4A15BA6A5A859D9EEDD6E4D0366286F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_2D2190B31505F1D6B6416E4D03669982" xlink:to="loc_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock_F4A15BA6A5A859D9EEDD6E4D0366286F" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/BusinessCombination" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationsAbstract" xlink:label="loc_us-gaap_BusinessCombinationsAbstract_9AA7F114844BF71557306E4D05B32A26" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationDisclosureTextBlock" xlink:label="loc_us-gaap_BusinessCombinationDisclosureTextBlock_E928F2C855BD7EDA3E506E4D05B39E2E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BusinessCombinationsAbstract_9AA7F114844BF71557306E4D05B32A26" xlink:to="loc_us-gaap_BusinessCombinationDisclosureTextBlock_E928F2C855BD7EDA3E506E4D05B39E2E" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/BusinessCombinationAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationsAbstract" xlink:label="loc_us-gaap_BusinessCombinationsAbstract_23FA0488A666175EE35193DC6FAC9B83" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2CA51DD0ED291E2661DB93DC6FAC6EB6" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BusinessCombinationsAbstract_23FA0488A666175EE35193DC6FAC9B83" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2CA51DD0ED291E2661DB93DC6FAC6EB6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_5FB2D8285D6FD89193EB93DC6FACC75B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2CA51DD0ED291E2661DB93DC6FAC6EB6" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_5FB2D8285D6FD89193EB93DC6FACC75B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_93E39E65195EB17ED4F193DC6FAD9A90" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_5FB2D8285D6FD89193EB93DC6FACC75B" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_93E39E65195EB17ED4F193DC6FAD9A90" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ZoneFoxHoldingsLimitedMember" xlink:label="loc_ftnt_ZoneFoxHoldingsLimitedMember_338577E469BAF61A1BF293DC6FAD5D19" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_93E39E65195EB17ED4F193DC6FAD9A90" xlink:to="loc_ftnt_ZoneFoxHoldingsLimitedMember_338577E469BAF61A1BF293DC6FAD5D19" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_BradfordNetworksInc.Member" xlink:label="loc_ftnt_BradfordNetworksInc.Member_DEE90E664E77D9CFEC4293DC6FAD4616" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_93E39E65195EB17ED4F193DC6FAD9A90" xlink:to="loc_ftnt_BradfordNetworksInc.Member_DEE90E664E77D9CFEC4293DC6FAD4616" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_FB375570FF33B5F7ADD793DC6FAD3D6E" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2CA51DD0ED291E2661DB93DC6FAC6EB6" xlink:to="loc_us-gaap_BusinessAcquisitionLineItems_FB375570FF33B5F7ADD793DC6FAD3D6E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_B60356C87D11361D347693DC6FAD172A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB375570FF33B5F7ADD793DC6FAD3D6E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_B60356C87D11361D347693DC6FAD172A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_F4215428BF0C9947031793DC6FAEC8DF" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/netLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB375570FF33B5F7ADD793DC6FAD3D6E" xlink:to="loc_us-gaap_Goodwill_F4215428BF0C9947031793DC6FAEC8DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_5461421ECB0E9574250793DC6FAE2E28" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB375570FF33B5F7ADD793DC6FAD3D6E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_5461421ECB0E9574250793DC6FAE2E28" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_9AE7FC78F742CC0AB05193DC6FAEB044" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB375570FF33B5F7ADD793DC6FAD3D6E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_9AE7FC78F742CC0AB05193DC6FAEB044" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh_21FA6FF18CBE99C97C6993DC6FAEBDC6" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB375570FF33B5F7ADD793DC6FAD3D6E" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh_21FA6FF18CBE99C97C6993DC6FAEBDC6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_23888D0F7EFAD70089B294641E5F3324" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB375570FF33B5F7ADD793DC6FAD3D6E" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_23888D0F7EFAD70089B294641E5F3324" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/CommitmentsAndContingencies" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_BD9DBEB1B3C13B2A8F6A6E4D028EE6EA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_64D3337D0809C3219FE06E4D028FA7A5" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_BD9DBEB1B3C13B2A8F6A6E4D028EE6EA" xlink:to="loc_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_64D3337D0809C3219FE06E4D028FA7A5" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/CommitmentsAndContingenciesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_831F04AE1458547D23E373ECD8ECB0C9" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PurchaseObligation" xlink:label="loc_us-gaap_PurchaseObligation_14608F015267C220FACE73ECD8ED729B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_831F04AE1458547D23E373ECD8ECB0C9" xlink:to="loc_us-gaap_PurchaseObligation_14608F015267C220FACE73ECD8ED729B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherCommitment" xlink:label="loc_us-gaap_OtherCommitment_E1A5E4D36D1F4249133373ECD8EDAA01" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_831F04AE1458547D23E373ECD8ECB0C9" xlink:to="loc_us-gaap_OtherCommitment_E1A5E4D36D1F4249133373ECD8EDAA01" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/CommitmentsAndContingenciesMinimumOperatingLeasePaymentsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_38263A7129EE1B37675F73ECD8F6F551" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PurchaseObligationFiscalYearMaturityAbstract" xlink:label="loc_us-gaap_PurchaseObligationFiscalYearMaturityAbstract_97DA281E6E1C09A2C5BF73ECD8F89481" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_38263A7129EE1B37675F73ECD8F6F551" xlink:to="loc_us-gaap_PurchaseObligationFiscalYearMaturityAbstract_97DA281E6E1C09A2C5BF73ECD8F89481" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PurchaseObligationFutureMinimumPaymentsRemainderOfFiscalYear" xlink:label="loc_us-gaap_PurchaseObligationFutureMinimumPaymentsRemainderOfFiscalYear_2C9430B18883321EF2FB73ECD8F836D1" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PurchaseObligationFiscalYearMaturityAbstract_97DA281E6E1C09A2C5BF73ECD8F89481" xlink:to="loc_us-gaap_PurchaseObligationFutureMinimumPaymentsRemainderOfFiscalYear_2C9430B18883321EF2FB73ECD8F836D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PurchaseObligationDueInSecondYear" xlink:label="loc_us-gaap_PurchaseObligationDueInSecondYear_B423BC0B92EED7D88B2C73ECD8F9C553" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PurchaseObligationFiscalYearMaturityAbstract_97DA281E6E1C09A2C5BF73ECD8F89481" xlink:to="loc_us-gaap_PurchaseObligationDueInSecondYear_B423BC0B92EED7D88B2C73ECD8F9C553" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PurchaseObligationDueInThirdYear" xlink:label="loc_us-gaap_PurchaseObligationDueInThirdYear_1FB2A1E3BDB079CAAD6473ECD8F9C451" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PurchaseObligationFiscalYearMaturityAbstract_97DA281E6E1C09A2C5BF73ECD8F89481" xlink:to="loc_us-gaap_PurchaseObligationDueInThirdYear_1FB2A1E3BDB079CAAD6473ECD8F9C451" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PurchaseObligationDueInFourthYear" xlink:label="loc_us-gaap_PurchaseObligationDueInFourthYear_11BD1746015DA8E29A5273ECD8F94C4E" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PurchaseObligationFiscalYearMaturityAbstract_97DA281E6E1C09A2C5BF73ECD8F89481" xlink:to="loc_us-gaap_PurchaseObligationDueInFourthYear_11BD1746015DA8E29A5273ECD8F94C4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PurchaseObligationDueInFifthYear" xlink:label="loc_us-gaap_PurchaseObligationDueInFifthYear_0562E2A09D9A669B36A373ECD8F9D7E6" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PurchaseObligationFiscalYearMaturityAbstract_97DA281E6E1C09A2C5BF73ECD8F89481" xlink:to="loc_us-gaap_PurchaseObligationDueInFifthYear_0562E2A09D9A669B36A373ECD8F9D7E6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PurchaseObligationDueAfterFifthYear" xlink:label="loc_us-gaap_PurchaseObligationDueAfterFifthYear_2BC71F13215F1858EF8B73ECD8F92F35" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PurchaseObligationFiscalYearMaturityAbstract_97DA281E6E1C09A2C5BF73ECD8F89481" xlink:to="loc_us-gaap_PurchaseObligationDueAfterFifthYear_2BC71F13215F1858EF8B73ECD8F92F35" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PurchaseObligation" xlink:label="loc_us-gaap_PurchaseObligation_7A0DE319E360B9F8EAB573ECD8F950AD" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PurchaseObligationFiscalYearMaturityAbstract_97DA281E6E1C09A2C5BF73ECD8F89481" xlink:to="loc_us-gaap_PurchaseObligation_7A0DE319E360B9F8EAB573ECD8F950AD" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/CommitmentsAndContingenciesTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_B93516551C79D0AE149A6E4D04B37BCE" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractualObligationFiscalYearMaturityScheduleTableTextBlock" xlink:label="loc_us-gaap_ContractualObligationFiscalYearMaturityScheduleTableTextBlock_72E5CBCA3A6D401CE7206E4D04B4F4B6" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_B93516551C79D0AE149A6E4D04B37BCE" xlink:to="loc_us-gaap_ContractualObligationFiscalYearMaturityScheduleTableTextBlock_72E5CBCA3A6D401CE7206E4D04B4F4B6" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/ConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract_002C6548496394A3FF138F6C31A16103" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_7EB8E19740F19D2025398F6C31A106CC" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_002C6548496394A3FF138F6C31A16103" xlink:to="loc_us-gaap_StatementTable_7EB8E19740F19D2025398F6C31A106CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_64B2701FC437A3D4496C8F6C31A1B2F8" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_7EB8E19740F19D2025398F6C31A106CC" xlink:to="loc_us-gaap_StatementScenarioAxis_64B2701FC437A3D4496C8F6C31A1B2F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_AB8D5D7B6388941C70088F6C31A5DF3B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementScenarioAxis_64B2701FC437A3D4496C8F6C31A1B2F8" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_AB8D5D7B6388941C70088F6C31A5DF3B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_40C74641134464A90B2E8F6C31A5F36D" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_7EB8E19740F19D2025398F6C31A106CC" xlink:to="loc_us-gaap_StatementLineItems_40C74641134464A90B2E8F6C31A5F36D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_5DC2D1F45E442306D52A8F6C31A5AE9A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_40C74641134464A90B2E8F6C31A5F36D" xlink:to="loc_us-gaap_AssetsAbstract_5DC2D1F45E442306D52A8F6C31A5AE9A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_B13460AA833391E7AADC8F6C31A56BE9" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_5DC2D1F45E442306D52A8F6C31A5AE9A" xlink:to="loc_us-gaap_AssetsCurrentAbstract_B13460AA833391E7AADC8F6C31A56BE9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_A4EEA2064FB7F850610C8F6C31A5694A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_B13460AA833391E7AADC8F6C31A56BE9" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_A4EEA2064FB7F850610C8F6C31A5694A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShortTermInvestments" xlink:label="loc_us-gaap_ShortTermInvestments_CEE92D179D004B609B818F6C31A5222F" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_B13460AA833391E7AADC8F6C31A56BE9" xlink:to="loc_us-gaap_ShortTermInvestments_CEE92D179D004B609B818F6C31A5222F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_CD49624583F85222B8FB8F6C31A5C1F1" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_B13460AA833391E7AADC8F6C31A56BE9" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_CD49624583F85222B8FB8F6C31A5C1F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_89D236EE4866E8FAB3538F6C31A52DC5" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_B13460AA833391E7AADC8F6C31A56BE9" xlink:to="loc_us-gaap_InventoryNet_89D236EE4866E8FAB3538F6C31A52DC5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_6C573285047BE8A533DD8F6C31A5AE54" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_B13460AA833391E7AADC8F6C31A56BE9" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_6C573285047BE8A533DD8F6C31A5AE54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_65214F7276CC02AF01E98F6C31A5C882" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_B13460AA833391E7AADC8F6C31A56BE9" xlink:to="loc_us-gaap_AssetsCurrent_65214F7276CC02AF01E98F6C31A5C882" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermInvestments" xlink:label="loc_us-gaap_LongTermInvestments_3614D99D76AFF3A1A6468F6C31A52C9E" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_5DC2D1F45E442306D52A8F6C31A5AE9A" xlink:to="loc_us-gaap_LongTermInvestments_3614D99D76AFF3A1A6468F6C31A52C9E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_FB443F42624066CA7F3A8F6C31A5C078" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_5DC2D1F45E442306D52A8F6C31A5AE9A" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_FB443F42624066CA7F3A8F6C31A5C078" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalizedContractCostNet" xlink:label="loc_us-gaap_CapitalizedContractCostNet_5461B9074127D89774C98F6C31A5E676" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_5DC2D1F45E442306D52A8F6C31A5AE9A" xlink:to="loc_us-gaap_CapitalizedContractCostNet_5461B9074127D89774C98F6C31A5E676" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_7FD7C07EFDFE84F17B018F7E018B3A6B" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_5DC2D1F45E442306D52A8F6C31A5AE9A" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_7FD7C07EFDFE84F17B018F7E018B3A6B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_DE508DA184D72294AA538F6C31A55EF6" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_5DC2D1F45E442306D52A8F6C31A5AE9A" xlink:to="loc_us-gaap_Goodwill_DE508DA184D72294AA538F6C31A55EF6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_54DB997045ED9026F7668F6C31A591AE" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_5DC2D1F45E442306D52A8F6C31A5AE9A" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_54DB997045ED9026F7668F6C31A591AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_18803DF61AB00F5518808F6C31A52F05" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_5DC2D1F45E442306D52A8F6C31A5AE9A" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_18803DF61AB00F5518808F6C31A52F05" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_483046583D84C9B4EFEF8F6C31A54E21" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_5DC2D1F45E442306D52A8F6C31A5AE9A" xlink:to="loc_us-gaap_Assets_483046583D84C9B4EFEF8F6C31A54E21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D07134272786E36D9E708F6C31A99ABB" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_40C74641134464A90B2E8F6C31A5F36D" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D07134272786E36D9E708F6C31A99ABB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_4F1FBE80147D6B7A48C98F6C31A9E686" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D07134272786E36D9E708F6C31A99ABB" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_4F1FBE80147D6B7A48C98F6C31A9E686" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaap_AccountsPayableCurrent_586FAE51E3975042E3998F6C31A96BDB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_4F1FBE80147D6B7A48C98F6C31A9E686" xlink:to="loc_us-gaap_AccountsPayableCurrent_586FAE51E3975042E3998F6C31A96BDB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_7083E778AA71D59E9A8A8F6C31A95AE8" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_4F1FBE80147D6B7A48C98F6C31A9E686" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_7083E778AA71D59E9A8A8F6C31A95AE8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_8E85C73EDD4718C5D3598F6C31AAA906" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_4F1FBE80147D6B7A48C98F6C31A9E686" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_8E85C73EDD4718C5D3598F6C31AAA906" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccruedIncomeTaxesCurrent" xlink:label="loc_us-gaap_AccruedIncomeTaxesCurrent_361C0D3A1DCEE6E6471D8F6C31AA3C69" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_4F1FBE80147D6B7A48C98F6C31A9E686" xlink:to="loc_us-gaap_AccruedIncomeTaxesCurrent_361C0D3A1DCEE6E6471D8F6C31AA3C69" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_49066E0E636924269EA68F6C31AA2043" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_4F1FBE80147D6B7A48C98F6C31A9E686" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_49066E0E636924269EA68F6C31AA2043" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_F29507977F06490D2EBA8F6C31AAB3B8" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_4F1FBE80147D6B7A48C98F6C31A9E686" xlink:to="loc_us-gaap_LiabilitiesCurrent_F29507977F06490D2EBA8F6C31AAB3B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_F5153F7921D6DC9DAE7A8F6C31AA4BD5" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D07134272786E36D9E708F6C31A99ABB" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_F5153F7921D6DC9DAE7A8F6C31AA4BD5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccruedIncomeTaxesNoncurrent" xlink:label="loc_us-gaap_AccruedIncomeTaxesNoncurrent_F76E156C3684CAFF55A18F6C31AB4FF0" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D07134272786E36D9E708F6C31A99ABB" xlink:to="loc_us-gaap_AccruedIncomeTaxesNoncurrent_F76E156C3684CAFF55A18F6C31AB4FF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_C51BB3D08BC10D365BBC8F6C31AB4494" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D07134272786E36D9E708F6C31A99ABB" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_C51BB3D08BC10D365BBC8F6C31AB4494" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_64D8616EF3F42D1FBFF08F6C31AB2410" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D07134272786E36D9E708F6C31A99ABB" xlink:to="loc_us-gaap_Liabilities_64D8616EF3F42D1FBFF08F6C31AB2410" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies_4727F5E81D456F40A1748F6C31AB2C08" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D07134272786E36D9E708F6C31A99ABB" xlink:to="loc_us-gaap_CommitmentsAndContingencies_4727F5E81D456F40A1748F6C31AB2C08" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaap_StockholdersEquityAbstract_CF0937F16855310A68758F6C31ABD9F6" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D07134272786E36D9E708F6C31A99ABB" xlink:to="loc_us-gaap_StockholdersEquityAbstract_CF0937F16855310A68758F6C31ABD9F6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue_9CED2318742ECB7DA1868F6C31AB99BB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_CF0937F16855310A68758F6C31ABD9F6" xlink:to="loc_us-gaap_CommonStockValue_9CED2318742ECB7DA1868F6C31AB99BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_E0361635F07A9C358CDB8F6C31AB58FA" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_CF0937F16855310A68758F6C31ABD9F6" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_E0361635F07A9C358CDB8F6C31AB58FA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_723801326D7532C638818F6C31ABEC1E" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_CF0937F16855310A68758F6C31ABD9F6" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_723801326D7532C638818F6C31ABEC1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_2ED886F395ACDFEC32498F6C31AB2C1E" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_CF0937F16855310A68758F6C31ABD9F6" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_2ED886F395ACDFEC32498F6C31AB2C1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_EBBC0A1E190AE86CDB118F6C31AB389C" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_CF0937F16855310A68758F6C31ABD9F6" xlink:to="loc_us-gaap_StockholdersEquity_EBBC0A1E190AE86CDB118F6C31AB389C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_E01C66CF96C19A5711888F6C31ABE003" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_D07134272786E36D9E708F6C31A99ABB" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_E01C66CF96C19A5711888F6C31ABE003" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract_4D01459DFC1C10875D336E4D02A0A495" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_151B74DF7C946265339A6E4D02A02342" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_4D01459DFC1C10875D336E4D02A0A495" xlink:to="loc_us-gaap_StatementTable_151B74DF7C946265339A6E4D02A02342" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_40CCF132378A30C3D8986E4D02A0FD9D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_151B74DF7C946265339A6E4D02A02342" xlink:to="loc_us-gaap_StatementScenarioAxis_40CCF132378A30C3D8986E4D02A0FD9D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_B3D30E31992510BC86CC6E4D02A188EB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementScenarioAxis_40CCF132378A30C3D8986E4D02A0FD9D" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_B3D30E31992510BC86CC6E4D02A188EB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_92C57BC88ACA2C6882D46E4D02A145FC" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_151B74DF7C946265339A6E4D02A02342" xlink:to="loc_us-gaap_StatementLineItems_92C57BC88ACA2C6882D46E4D02A145FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_18263F864D986DDF88B16E4D02A18365" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_92C57BC88ACA2C6882D46E4D02A145FC" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_18263F864D986DDF88B16E4D02A18365" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_5BE54632A67CD654F1436E4D02A21919" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_92C57BC88ACA2C6882D46E4D02A145FC" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_5BE54632A67CD654F1436E4D02A21919" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaap_CommonStockSharesIssued_9846A2E55B3E31E9F1736E4D02A2AB8D" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_92C57BC88ACA2C6882D46E4D02A145FC" xlink:to="loc_us-gaap_CommonStockSharesIssued_9846A2E55B3E31E9F1736E4D02A2AB8D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_BFD398382C32C998A0D86E4D02A29E3A" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_92C57BC88ACA2C6882D46E4D02A145FC" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_BFD398382C32C998A0D86E4D02A29E3A" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:label="loc_us-gaap_StatementOfCashFlowsAbstract_690D5B967304D43EBB9C8FF53B19DE5C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_5CFE1B7F3109A1A4C93C8FF53B19C211" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_690D5B967304D43EBB9C8FF53B19DE5C" xlink:to="loc_us-gaap_StatementTable_5CFE1B7F3109A1A4C93C8FF53B19C211" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_2E0B0DB8F99615499EF98FF53B19F7F8" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_5CFE1B7F3109A1A4C93C8FF53B19C211" xlink:to="loc_us-gaap_StatementScenarioAxis_2E0B0DB8F99615499EF98FF53B19F7F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_D4050F7306991A410CDA8FF53B1A8AF2" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementScenarioAxis_2E0B0DB8F99615499EF98FF53B19F7F8" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_D4050F7306991A410CDA8FF53B1A8AF2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_6426034F410F3D118C928FF53B1A75E6" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_5CFE1B7F3109A1A4C93C8FF53B19C211" xlink:to="loc_us-gaap_StatementLineItems_6426034F410F3D118C928FF53B1A75E6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_588B5F1C156ABCE78E408FF53B1A2B84" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_6426034F410F3D118C928FF53B1A75E6" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_588B5F1C156ABCE78E408FF53B1A2B84" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_D9E330B4D2B0739542928FF53B1AF040" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_588B5F1C156ABCE78E408FF53B1A2B84" xlink:to="loc_us-gaap_NetIncomeLoss_D9E330B4D2B0739542928FF53B1AF040" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_0871546B1CEAAA790CF28FF53B1BCDCF" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_588B5F1C156ABCE78E408FF53B1A2B84" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_0871546B1CEAAA790CF28FF53B1BCDCF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_B4D56D0CCDF8E3A301708FF53B1B9CC3" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_0871546B1CEAAA790CF28FF53B1BCDCF" xlink:to="loc_us-gaap_ShareBasedCompensation_B4D56D0CCDF8E3A301708FF53B1B9CC3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalizedContractCostAmortization" xlink:label="loc_us-gaap_CapitalizedContractCostAmortization_5B54FBBCD5DBBF83D3348FF53B1BFF62" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_0871546B1CEAAA790CF28FF53B1BCDCF" xlink:to="loc_us-gaap_CapitalizedContractCostAmortization_5B54FBBCD5DBBF83D3348FF53B1BFF62" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_7DF23F9E506E08B24AE88FF53B1B3CED" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_0871546B1CEAAA790CF28FF53B1BCDCF" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_7DF23F9E506E08B24AE88FF53B1B3CED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xlink:label="loc_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_C4E89EF12DE8E464A5188FF53B1C978D" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_0871546B1CEAAA790CF28FF53B1BCDCF" xlink:to="loc_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_C4E89EF12DE8E464A5188FF53B1C978D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNoncashIncomeExpense" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_6B296967F17FBC47090C8FF53B1CD44A" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_0871546B1CEAAA790CF28FF53B1BCDCF" xlink:to="loc_us-gaap_OtherNoncashIncomeExpense_6B296967F17FBC47090C8FF53B1CD44A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_588B5F1C156ABCE78E408FF53B1A2B84" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_002BFDF19FE25CC73F8C8FF53B1C124D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_002BFDF19FE25CC73F8C8FF53B1C124D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_00F642A05EECD29717B98FF53B1C3C32" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_00F642A05EECD29717B98FF53B1C3C32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_6278F277914EC4EB1CA68FF53B1D29FD" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_6278F277914EC4EB1CA68FF53B1D29FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredCharges" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredCharges_901D286B57D7F513D2F58FF53B1D8895" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredCharges_901D286B57D7F513D2F58FF53B1D8895" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredIncomeTaxes" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredIncomeTaxes_EDCD5B76D1E664ABF8C28FF53B1D7125" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredIncomeTaxes_EDCD5B76D1E664ABF8C28FF53B1D7125" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_BEA0E3B6012A2A7B4BDF8FF53B1D13B3" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets_BEA0E3B6012A2A7B4BDF8FF53B1D13B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_422272D44B73693EDE478FF53B1D0193" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_422272D44B73693EDE478FF53B1D0193" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_899D4FC11E392129B6998FF53B1DB573" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_899D4FC11E392129B6998FF53B1DB573" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_D87F1FC0904CE10B4BBD8FF53B1E748C" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:to="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_D87F1FC0904CE10B4BBD8FF53B1E748C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities_45D60F07CA61B034E6958FF53B1E69B4" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities_45D60F07CA61B034E6958FF53B1E69B4" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_IncreaseDecreaseInContractWithCustomerLiability" xlink:label="loc_ftnt_IncreaseDecreaseInContractWithCustomerLiability_01FFC2B62D89C7BA8CAE8FF53B1E777E" xlink:type="locator" />
    <link:presentationArc order="11" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:to="loc_ftnt_IncreaseDecreaseInContractWithCustomerLiability_01FFC2B62D89C7BA8CAE8FF53B1E777E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_647EAD3E8A31090184DF8FF53B1E6413" xlink:type="locator" />
    <link:presentationArc order="12" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract_73EBB50A251041D51D478FF53B1C7347" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_647EAD3E8A31090184DF8FF53B1E6413" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_273EBD798C36325943F48FF53B1EA853" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_588B5F1C156ABCE78E408FF53B1A2B84" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_273EBD798C36325943F48FF53B1EA853" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_5116FC7E454B6E47B50B8FF53B1E1DD4" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_6426034F410F3D118C928FF53B1A75E6" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_5116FC7E454B6E47B50B8FF53B1E1DD4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireInvestments" xlink:label="loc_us-gaap_PaymentsToAcquireInvestments_C82A641B6582307DCD8E8FF53B1FFC06" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_5116FC7E454B6E47B50B8FF53B1E1DD4" xlink:to="loc_us-gaap_PaymentsToAcquireInvestments_C82A641B6582307DCD8E8FF53B1FFC06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt" xlink:label="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_6463635F8ACEECAFFDEB8FF53B1FC3EC" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_5116FC7E454B6E47B50B8FF53B1E1DD4" xlink:to="loc_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_6463635F8ACEECAFFDEB8FF53B1FC3EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:label="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_A87C8F6C7CE1A5ED9C748FF53B2445C2" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_5116FC7E454B6E47B50B8FF53B1E1DD4" xlink:to="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_A87C8F6C7CE1A5ED9C748FF53B2445C2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_B49483E6C9D044931B948FF53B246640" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_5116FC7E454B6E47B50B8FF53B1E1DD4" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_B49483E6C9D044931B948FF53B246640" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_561570F9ECCC15E2ED098FF53B244BC6" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_5116FC7E454B6E47B50B8FF53B1E1DD4" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_561570F9ECCC15E2ED098FF53B244BC6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_458CE693F5462652A6E48FF53B253122" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_6426034F410F3D118C928FF53B1A75E6" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_458CE693F5462652A6E48FF53B253122" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_4EAD2CD5659A0628858D8FF53B25EC60" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_458CE693F5462652A6E48FF53B253122" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_4EAD2CD5659A0628858D8FF53B25EC60" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_C38CEDA65E499C4482798FF53B256CA4" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_458CE693F5462652A6E48FF53B253122" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_C38CEDA65E499C4482798FF53B256CA4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_B935A4105BC813BE06918FF53B256074" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_458CE693F5462652A6E48FF53B253122" xlink:to="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_B935A4105BC813BE06918FF53B256074" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_37864D28AC6DE9C30E878FF53B254A84" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_458CE693F5462652A6E48FF53B253122" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_37864D28AC6DE9C30E878FF53B254A84" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_781E6585BED96B5A93518FF53B269BA2" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_6426034F410F3D118C928FF53B1A75E6" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_781E6585BED96B5A93518FF53B269BA2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_E409F6514D2A56B3758C8FF53B26C754" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_6426034F410F3D118C928FF53B1A75E6" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_E409F6514D2A56B3758C8FF53B26C754" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_CBD7EB484A241B23DF8B8FF53B2641C3" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_6426034F410F3D118C928FF53B1A75E6" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_CBD7EB484A241B23DF8B8FF53B2641C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_8E8DED89A343C379C4FF8FF53B266571" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_6426034F410F3D118C928FF53B1A75E6" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_8E8DED89A343C379C4FF8FF53B266571" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_LeaseLiabilityArisingfromObtainingRightofUseAsset" xlink:label="loc_ftnt_LeaseLiabilityArisingfromObtainingRightofUseAsset_4665F2AE8D71ABEE40398FF53B26ADC4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_8E8DED89A343C379C4FF8FF53B266571" xlink:to="loc_ftnt_LeaseLiabilityArisingfromObtainingRightofUseAsset_4665F2AE8D71ABEE40398FF53B26ADC4" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_RepurchaseofCommonStockSettlementofLiabilitiesIncurred" xlink:label="loc_ftnt_RepurchaseofCommonStockSettlementofLiabilitiesIncurred_C92BFFE7F8CB8554F1B78FFC496A8C74" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_8E8DED89A343C379C4FF8FF53B266571" xlink:to="loc_ftnt_RepurchaseofCommonStockSettlementofLiabilitiesIncurred_C92BFFE7F8CB8554F1B78FFC496A8C74" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:label="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_CBF00CDE30D50F76E6E58FF53B26528F" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_6426034F410F3D118C928FF53B1A75E6" xlink:to="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_CBF00CDE30D50F76E6E58FF53B26528F" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_TransfersofEvaluationUnitsfromInventorytoPropertyandEquipment" xlink:label="loc_ftnt_TransfersofEvaluationUnitsfromInventorytoPropertyandEquipment_B33E6BAE3D5CB96D9E4C8FF53B274CA1" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_CBF00CDE30D50F76E6E58FF53B26528F" xlink:to="loc_ftnt_TransfersofEvaluationUnitsfromInventorytoPropertyandEquipment_B33E6BAE3D5CB96D9E4C8FF53B274CA1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_FF6B9284126965B3BECD8FF53B27285F" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_CBF00CDE30D50F76E6E58FF53B26528F" xlink:to="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_FF6B9284126965B3BECD8FF53B27285F" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:label="loc_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_C62CE07C8BD35103F3226E4D033EDB2A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_D4DBF46F5B7F281CCC396E4D033E5522" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_C62CE07C8BD35103F3226E4D033EDB2A" xlink:to="loc_us-gaap_StatementTable_D4DBF46F5B7F281CCC396E4D033E5522" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_5E9AAC88E3FD0603817D6E4D033E5D23" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_D4DBF46F5B7F281CCC396E4D033E5522" xlink:to="loc_us-gaap_StatementScenarioAxis_5E9AAC88E3FD0603817D6E4D033E5D23" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_7466FE9DF685A52015B36E4D033FFBDB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementScenarioAxis_5E9AAC88E3FD0603817D6E4D033E5D23" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_7466FE9DF685A52015B36E4D033FFBDB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_5AA81356320D946039806E4D03401634" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_D4DBF46F5B7F281CCC396E4D033E5522" xlink:to="loc_us-gaap_StatementLineItems_5AA81356320D946039806E4D03401634" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_80F0023C99E875D16F3C6E4D03407653" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5AA81356320D946039806E4D03401634" xlink:to="loc_us-gaap_NetIncomeLoss_80F0023C99E875D16F3C6E4D03407653" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParentAbstract" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParentAbstract_741EFF4950315C31399D6E4D034046C4" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5AA81356320D946039806E4D03401634" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParentAbstract_741EFF4950315C31399D6E4D034046C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax_8718E651E3963C0B56A16E4D034127F1" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParentAbstract_741EFF4950315C31399D6E4D034046C4" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax_8718E651E3963C0B56A16E4D034127F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_09742110570DB0898C806E4D03417E98" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParentAbstract_741EFF4950315C31399D6E4D034046C4" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_09742110570DB0898C806E4D03417E98" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_034FE526F72A615041016E4D0342934A" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParentAbstract_741EFF4950315C31399D6E4D034046C4" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_034FE526F72A615041016E4D0342934A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_6E87807775A1E138AF2E6E4D03424438" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5AA81356320D946039806E4D03401634" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_6E87807775A1E138AF2E6E4D03424438" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/ConsolidatedStatementsOfIncome" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementAbstract" xlink:label="loc_us-gaap_IncomeStatementAbstract_9FF944EC7DB6EFC25B748F6C318A9D0B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_2D6B22D81C5145BCD6238F6C318A2455" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_9FF944EC7DB6EFC25B748F6C318A9D0B" xlink:to="loc_us-gaap_StatementTable_2D6B22D81C5145BCD6238F6C318A2455" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="loc_us-gaap_ProductOrServiceAxis_F7E43C2AEF334B828DDB8F6C318A381E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_2D6B22D81C5145BCD6238F6C318A2455" xlink:to="loc_us-gaap_ProductOrServiceAxis_F7E43C2AEF334B828DDB8F6C318A381E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_5380E33A678B4D4F3FBC8F6C318A0D30" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductOrServiceAxis_F7E43C2AEF334B828DDB8F6C318A381E" xlink:to="loc_us-gaap_ProductsAndServicesDomain_5380E33A678B4D4F3FBC8F6C318A0D30" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductMember" xlink:label="loc_us-gaap_ProductMember_7DED51DD169B1EC67F028F6C318BDA19" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_5380E33A678B4D4F3FBC8F6C318A0D30" xlink:to="loc_us-gaap_ProductMember_7DED51DD169B1EC67F028F6C318BDA19" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ServiceMember" xlink:label="loc_ftnt_ServiceMember_E15072FED5D66CA53B498F6C318B4B3C" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_5380E33A678B4D4F3FBC8F6C318A0D30" xlink:to="loc_ftnt_ServiceMember_E15072FED5D66CA53B498F6C318B4B3C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_2D6B22D81C5145BCD6238F6C318A2455" xlink:to="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesRevenueNetAbstract" xlink:label="loc_us-gaap_SalesRevenueNetAbstract_17A6342FB3540F107EA78F6C318B0DDA" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:to="loc_us-gaap_SalesRevenueNetAbstract_17A6342FB3540F107EA78F6C318B0DDA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_D2D0A76C3B5CD39D9F0D8F6C318B2E3E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SalesRevenueNetAbstract_17A6342FB3540F107EA78F6C318B0DDA" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_D2D0A76C3B5CD39D9F0D8F6C318B2E3E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfGoodsAndServicesSoldAbstract" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSoldAbstract_EFA4DB72EF888FBA82AB8F6C318BEEBA" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSoldAbstract_EFA4DB72EF888FBA82AB8F6C318BEEBA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_3A22BBBFB0E3C374B0368F6C318B4417" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CostOfGoodsAndServicesSoldAbstract_EFA4DB72EF888FBA82AB8F6C318BEEBA" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_3A22BBBFB0E3C374B0368F6C318B4417" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GrossProfitAbstract" xlink:label="loc_us-gaap_GrossProfitAbstract_F0862D354F3A374900CF8F6C318BA2D6" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:to="loc_us-gaap_GrossProfitAbstract_F0862D354F3A374900CF8F6C318BA2D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_FE67A157766638126F018F6C318BCB4A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GrossProfitAbstract_F0862D354F3A374900CF8F6C318BA2D6" xlink:to="loc_us-gaap_GrossProfit_FE67A157766638126F018F6C318BCB4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="loc_us-gaap_OperatingExpensesAbstract_4868941D90DABC099C1B8F6C318BDC71" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:to="loc_us-gaap_OperatingExpensesAbstract_4868941D90DABC099C1B8F6C318BDC71" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_E8F0878355DECDD76AEC8F6C318BC39C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_4868941D90DABC099C1B8F6C318BDC71" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_E8F0878355DECDD76AEC8F6C318BC39C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="loc_us-gaap_SellingAndMarketingExpense_CC995CF43B6464CE8ACE8F6C318B8CE1" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_4868941D90DABC099C1B8F6C318BDC71" xlink:to="loc_us-gaap_SellingAndMarketingExpense_CC995CF43B6464CE8ACE8F6C318B8CE1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_B24FAF11D1010FE121D68F6C318BCC5C" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_4868941D90DABC099C1B8F6C318BDC71" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_B24FAF11D1010FE121D68F6C318BCC5C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaap_OperatingExpenses_820147FC5399CA4910AE8F6C318B2892" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_4868941D90DABC099C1B8F6C318BDC71" xlink:to="loc_us-gaap_OperatingExpenses_820147FC5399CA4910AE8F6C318B2892" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_A75D711BE432EE8A7AE48F6C318B0522" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:to="loc_us-gaap_OperatingIncomeLoss_A75D711BE432EE8A7AE48F6C318B0522" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentIncomeNet" xlink:label="loc_us-gaap_InvestmentIncomeNet_6823A8662DEDE820007C8F6C318B9E38" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:to="loc_us-gaap_InvestmentIncomeNet_6823A8662DEDE820007C8F6C318B9E38" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_46C57848021BBAF346108F6C318B3DB1" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_46C57848021BBAF346108F6C318B3DB1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_D3607ADBBA4711D785FC8F6C318BC8EF" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_D3607ADBBA4711D785FC8F6C318BC8EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_2F0829D584551EEC7EE78F6C318B5850" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_2F0829D584551EEC7EE78F6C318B5850" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_FCBE28E36DA6B409E0658F6C318B2E1F" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:to="loc_us-gaap_NetIncomeLoss_FCBE28E36DA6B409E0658F6C318B2E1F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract_896C622EC0516C1023CD8F6C318B7B1D" xlink:type="locator" />
    <link:presentationArc order="11" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:to="loc_us-gaap_EarningsPerShareAbstract_896C622EC0516C1023CD8F6C318B7B1D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="loc_us-gaap_EarningsPerShareBasic_60F555766CC15E8D2C158F6C318F898C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_896C622EC0516C1023CD8F6C318B7B1D" xlink:to="loc_us-gaap_EarningsPerShareBasic_60F555766CC15E8D2C158F6C318F898C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="loc_us-gaap_EarningsPerShareDiluted_FC26BD5D6CC3D685ED2D8F6C318F6896" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_896C622EC0516C1023CD8F6C318B7B1D" xlink:to="loc_us-gaap_EarningsPerShareDiluted_FC26BD5D6CC3D685ED2D8F6C318F6896" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_5C0859E2C69C1B62B2AD8F6C318F2CA7" xlink:type="locator" />
    <link:presentationArc order="12" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_086897F8A947795A501F8F6C318BA42E" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_5C0859E2C69C1B62B2AD8F6C318F2CA7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_5DE8B5D4C0D378278CCA8F6C318F10D6" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_5C0859E2C69C1B62B2AD8F6C318F2CA7" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_5DE8B5D4C0D378278CCA8F6C318F10D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_53D67E3974CD331206768F6C31904BA2" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_5C0859E2C69C1B62B2AD8F6C318F2CA7" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_53D67E3974CD331206768F6C31904BA2" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/ConsolidatedStatementsOfStockholdersEquity" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementOfStockholdersEquityAbstract" xlink:label="loc_us-gaap_StatementOfStockholdersEquityAbstract_220F96615082036F8572748F71F44007" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_F2378A5E22BCDF97F03A748F71F412B4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfStockholdersEquityAbstract_220F96615082036F8572748F71F44007" xlink:to="loc_us-gaap_StatementTable_F2378A5E22BCDF97F03A748F71F412B4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_2225A73E3FA9C37171DB748F71F42E16" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_F2378A5E22BCDF97F03A748F71F412B4" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_2225A73E3FA9C37171DB748F71F42E16" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_BA36F5D53C88DB2D3439748F71F4326E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_2225A73E3FA9C37171DB748F71F42E16" xlink:to="loc_us-gaap_EquityComponentDomain_BA36F5D53C88DB2D3439748F71F4326E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_D421B868522532CBCC75748F71F43366" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_BA36F5D53C88DB2D3439748F71F4326E" xlink:to="loc_us-gaap_CommonStockMember_D421B868522532CBCC75748F71F43366" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_3A6D56127B8BBDE05939748F71F51FE3" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_BA36F5D53C88DB2D3439748F71F4326E" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_3A6D56127B8BBDE05939748F71F51FE3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_4A1E6FBD4FE4AE855F0D748F71F5FA20" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_BA36F5D53C88DB2D3439748F71F4326E" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_4A1E6FBD4FE4AE855F0D748F71F5FA20" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_E1B27DE12657F057F1F0748F71F5310F" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_BA36F5D53C88DB2D3439748F71F4326E" xlink:to="loc_us-gaap_RetainedEarningsMember_E1B27DE12657F057F1F0748F71F5310F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_BD04A1A2B1D46A245C64748F71F5495D" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_F2378A5E22BCDF97F03A748F71F412B4" xlink:to="loc_us-gaap_StatementLineItems_BD04A1A2B1D46A245C64748F71F5495D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_BD04A1A2B1D46A245C64748F71F5495D" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharesIssued" xlink:label="loc_us-gaap_SharesIssued_7FCA6756AB965B8508FA748F71F63400" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:to="loc_us-gaap_SharesIssued_7FCA6756AB965B8508FA748F71F63400" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_DB3EE731528A1B927119748F71F6B8BA" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:to="loc_us-gaap_StockholdersEquity_DB3EE731528A1B927119748F71F6B8BA" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_StockIssuedDuringPeriodSharesEquityIncentivePlans" xlink:label="loc_ftnt_StockIssuedDuringPeriodSharesEquityIncentivePlans_97D88D1A262D7CBE4182748F71F61E19" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:to="loc_ftnt_StockIssuedDuringPeriodSharesEquityIncentivePlans_97D88D1A262D7CBE4182748F71F61E19" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_StockIssuedDuringPeriodValueEquityIncentivePlansNetofTaxesWithheld" xlink:label="loc_ftnt_StockIssuedDuringPeriodValueEquityIncentivePlansNetofTaxesWithheld_2172E98B6F8FED0CB78E748F71F6440A" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:to="loc_ftnt_StockIssuedDuringPeriodValueEquityIncentivePlansNetofTaxesWithheld_2172E98B6F8FED0CB78E748F71F6440A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_2C2470725D0A54EDF6E0748F71F78C7C" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_2C2470725D0A54EDF6E0748F71F78C7C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_1CFCABEC92A633C4A6B9748F71F77FED" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_1CFCABEC92A633C4A6B9748F71F77FED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_3CBF1C2CA7177A1E3099748F71F729F2" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_3CBF1C2CA7177A1E3099748F71F729F2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_7720DE120051B8672358748F71F79949" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:to="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_7720DE120051B8672358748F71F79949" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_115F3124B46DA1D17C75748F71F72545" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_115F3124B46DA1D17C75748F71F72545" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_E2D1DFAB416B46EDDCA7748F71F7AB80" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:to="loc_us-gaap_NetIncomeLoss_E2D1DFAB416B46EDDCA7748F71F7AB80" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharesIssued" xlink:label="loc_us-gaap_SharesIssued_B3622F2A172C148DDB71748F71F7235C" xlink:type="locator" />
    <link:presentationArc order="11" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:to="loc_us-gaap_SharesIssued_B3622F2A172C148DDB71748F71F7235C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_AA5C18ABF78E47FAE78D748F71F82411" xlink:type="locator" />
    <link:presentationArc order="12" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_041EB1DB48FB7D6AE6E3748F71F5F789" xlink:to="loc_us-gaap_StockholdersEquity_AA5C18ABF78E47FAE78D748F71F82411" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/DefinedContributionPlans" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CompensationAndRetirementDisclosureAbstract" xlink:label="loc_us-gaap_CompensationAndRetirementDisclosureAbstract_855821DFD40EB8EE00917A6C0CED137A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CompensationAndEmployeeBenefitPlansTextBlock" xlink:label="loc_us-gaap_CompensationAndEmployeeBenefitPlansTextBlock_F884B2886B4D7421D9987A6C0CEE25BC" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CompensationAndRetirementDisclosureAbstract_855821DFD40EB8EE00917A6C0CED137A" xlink:to="loc_us-gaap_CompensationAndEmployeeBenefitPlansTextBlock_F884B2886B4D7421D9987A6C0CEE25BC" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/DefinedContributionPlansDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CompensationAndRetirementDisclosureAbstract" xlink:label="loc_us-gaap_CompensationAndRetirementDisclosureAbstract_2C0E945BF96F60D31A1B7A6C0CEB13D8" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch" xlink:label="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_3DA26BD9982835F9EC177A6C0CEBA895" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CompensationAndRetirementDisclosureAbstract_2C0E945BF96F60D31A1B7A6C0CEB13D8" xlink:to="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_3DA26BD9982835F9EC177A6C0CEBA895" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent" xlink:label="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_0F8D5DB71D1D73A3094A7A6C0CEB1127" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CompensationAndRetirementDisclosureAbstract_2C0E945BF96F60D31A1B7A6C0CEB13D8" xlink:to="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_0F8D5DB71D1D73A3094A7A6C0CEB1127" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_DefinedContributionPlanEmployerMatchingContributionAmount" xlink:label="loc_ftnt_DefinedContributionPlanEmployerMatchingContributionAmount_70699ECD4903A44D37327A6C0CEB8ED1" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CompensationAndRetirementDisclosureAbstract_2C0E945BF96F60D31A1B7A6C0CEB13D8" xlink:to="loc_ftnt_DefinedContributionPlanEmployerMatchingContributionAmount_70699ECD4903A44D37327A6C0CEB8ED1" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/DocumentAndEntityInformation" xlink:type="extended">
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_DeiAbstract" xlink:label="loc_ftnt_DeiAbstract_86CC3384AF86A738E49473DCDA440FF8" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityRegistrantName" xlink:label="loc_dei_EntityRegistrantName_6140AD26D3DE64F9DDEB73DCDA46EE6C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_DeiAbstract_86CC3384AF86A738E49473DCDA440FF8" xlink:to="loc_dei_EntityRegistrantName_6140AD26D3DE64F9DDEB73DCDA46EE6C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="loc_dei_EntityCentralIndexKey_172746797E85291DB25473DCDA4784BC" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_DeiAbstract_86CC3384AF86A738E49473DCDA440FF8" xlink:to="loc_dei_EntityCentralIndexKey_172746797E85291DB25473DCDA4784BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentType" xlink:label="loc_dei_DocumentType_7160C2E6423722F63D1573DCDA47F341" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_DeiAbstract_86CC3384AF86A738E49473DCDA440FF8" xlink:to="loc_dei_DocumentType_7160C2E6423722F63D1573DCDA47F341" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_0F69DCEB467B24EE936F73DCDA47ADF3" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_DeiAbstract_86CC3384AF86A738E49473DCDA440FF8" xlink:to="loc_dei_DocumentPeriodEndDate_0F69DCEB467B24EE936F73DCDA47ADF3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_AmendmentFlag" xlink:label="loc_dei_AmendmentFlag_8636404F295E6A6E1DD373DCDA48AFED" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_DeiAbstract_86CC3384AF86A738E49473DCDA440FF8" xlink:to="loc_dei_AmendmentFlag_8636404F295E6A6E1DD373DCDA48AFED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalYearFocus" xlink:label="loc_dei_DocumentFiscalYearFocus_BA0E5C09575AB514A59573DCDA4873F0" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_DeiAbstract_86CC3384AF86A738E49473DCDA440FF8" xlink:to="loc_dei_DocumentFiscalYearFocus_BA0E5C09575AB514A59573DCDA4873F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="loc_dei_DocumentFiscalPeriodFocus_FA33339B6A84C4065E7873DCDA484FAA" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_DeiAbstract_86CC3384AF86A738E49473DCDA440FF8" xlink:to="loc_dei_DocumentFiscalPeriodFocus_FA33339B6A84C4065E7873DCDA484FAA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:label="loc_dei_CurrentFiscalYearEndDate_B7E146A35EDC30910E3873DCDA48CAFD" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_DeiAbstract_86CC3384AF86A738E49473DCDA440FF8" xlink:to="loc_dei_CurrentFiscalYearEndDate_B7E146A35EDC30910E3873DCDA48CAFD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCurrentReportingStatus" xlink:label="loc_dei_EntityCurrentReportingStatus_A6BE16C2F75BFCCEB62F73DCDA48DFEB" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_DeiAbstract_86CC3384AF86A738E49473DCDA440FF8" xlink:to="loc_dei_EntityCurrentReportingStatus_A6BE16C2F75BFCCEB62F73DCDA48DFEB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityFilerCategory" xlink:label="loc_dei_EntityFilerCategory_7386627B4F6EAFF1640873DCDA483C62" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_DeiAbstract_86CC3384AF86A738E49473DCDA440FF8" xlink:to="loc_dei_EntityFilerCategory_7386627B4F6EAFF1640873DCDA483C62" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_AD4164F1ED364C745C0D73DCDA499690" xlink:type="locator" />
    <link:presentationArc order="11" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_DeiAbstract_86CC3384AF86A738E49473DCDA440FF8" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_AD4164F1ED364C745C0D73DCDA499690" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/FinancialInstrumentsAndFairValue" xlink:type="extended">
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_FinancialInstrumentsAndFairValueAbstract" xlink:label="loc_ftnt_FinancialInstrumentsAndFairValueAbstract_80B283621B5A0CA5378A6E4D03541FF3" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FinancialInstrumentsDisclosureTextBlock" xlink:label="loc_us-gaap_FinancialInstrumentsDisclosureTextBlock_40CFAF9E97A327C422E76E4D03540DAC" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_FinancialInstrumentsAndFairValueAbstract_80B283621B5A0CA5378A6E4D03541FF3" xlink:to="loc_us-gaap_FinancialInstrumentsDisclosureTextBlock_40CFAF9E97A327C422E76E4D03540DAC" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/FinancialInstrumentsAndFairValueFairValueMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_FinancialInstrumentsAndFairValueAbstract" xlink:label="loc_ftnt_FinancialInstrumentsAndFairValueAbstract_B0C32A3F5D5D4EA734C993DC6FF6DE85" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_E215CD5D1C3566E60FA893DC6FF6E3AD" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_FinancialInstrumentsAndFairValueAbstract_B0C32A3F5D5D4EA734C993DC6FF6DE85" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_E215CD5D1C3566E60FA893DC6FF6E3AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_031EB8F336A7224525A593DC6FF77C31" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_E215CD5D1C3566E60FA893DC6FF6E3AD" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_031EB8F336A7224525A593DC6FF77C31" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_A637EB40A88761846EF593DC6FF725DE" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_031EB8F336A7224525A593DC6FF77C31" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_A637EB40A88761846EF593DC6FF725DE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_58BA889C4115FE48FBF393DC6FF77768" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_A637EB40A88761846EF593DC6FF725DE" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_58BA889C4115FE48FBF393DC6FF77768" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_F39D0A639E65B135AB2E93DC6FF88DD4" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_E215CD5D1C3566E60FA893DC6FF6E3AD" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_F39D0A639E65B135AB2E93DC6FF88DD4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_43783F738A33660FF5FF93DC6FF86A13" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_F39D0A639E65B135AB2E93DC6FF88DD4" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_43783F738A33660FF5FF93DC6FF86A13" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_8C523C82A62BE244EC6393DC6FF8FA58" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_43783F738A33660FF5FF93DC6FF86A13" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_8C523C82A62BE244EC6393DC6FF8FA58" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_9670B300B77BEB6F185C93DC6FF8A0F0" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_43783F738A33660FF5FF93DC6FF86A13" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_9670B300B77BEB6F185C93DC6FF8A0F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_9D636415A3DA8711383093DC6FF97DBF" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_43783F738A33660FF5FF93DC6FF86A13" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_9D636415A3DA8711383093DC6FF97DBF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_DC82B28C521B7A1F774E93DC6FF9C1DC" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_E215CD5D1C3566E60FA893DC6FF6E3AD" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_DC82B28C521B7A1F774E93DC6FF9C1DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_B9A8A2A295FA653531E793DC6FF9790E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_DC82B28C521B7A1F774E93DC6FF9C1DC" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_B9A8A2A295FA653531E793DC6FF9790E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_C822C2438DE3C0BC76CF93DC6FF91815" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_B9A8A2A295FA653531E793DC6FF9790E" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_C822C2438DE3C0BC76CF93DC6FF91815" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember" xlink:label="loc_us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_94B653D1863E5A9FE2AA93DC6FF9C361" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_B9A8A2A295FA653531E793DC6FF9790E" xlink:to="loc_us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_94B653D1863E5A9FE2AA93DC6FF9C361" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_CertificatesofDepositandTermDepositsMember" xlink:label="loc_ftnt_CertificatesofDepositandTermDepositsMember_439C0704F5F15B7F682A93E47979206C" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_B9A8A2A295FA653531E793DC6FF9790E" xlink:to="loc_ftnt_CertificatesofDepositandTermDepositsMember_439C0704F5F15B7F682A93E47979206C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_USTreasuryAndGovernmentMember" xlink:label="loc_us-gaap_USTreasuryAndGovernmentMember_959911484C1FE84ED0A393DC6FFADC1F" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_B9A8A2A295FA653531E793DC6FF9790E" xlink:to="loc_us-gaap_USTreasuryAndGovernmentMember_959911484C1FE84ED0A393DC6FFADC1F" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_MoneyMarketFundsExcludingCommercialPaperMember" xlink:label="loc_ftnt_MoneyMarketFundsExcludingCommercialPaperMember_79CD031BC36878ED029593DC6FFA3599" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_B9A8A2A295FA653531E793DC6FF9790E" xlink:to="loc_ftnt_MoneyMarketFundsExcludingCommercialPaperMember_79CD031BC36878ED029593DC6FFA3599" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_7C912E37D420AB8BF66393DC6FFA9BBB" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_E215CD5D1C3566E60FA893DC6FF6E3AD" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_7C912E37D420AB8BF66393DC6FFA9BBB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_E1C09B89C6077C85885693DC6FFA50A2" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_7C912E37D420AB8BF66393DC6FFA9BBB" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_E1C09B89C6077C85885693DC6FFA50A2" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_CashEquivalentsLineItemMember" xlink:label="loc_ftnt_CashEquivalentsLineItemMember_43AA77468BC939A19A1993DC6FFB284E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_E1C09B89C6077C85885693DC6FFA50A2" xlink:to="loc_ftnt_CashEquivalentsLineItemMember_43AA77468BC939A19A1993DC6FFB284E" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ShortTermInvestmentsLineItemMember" xlink:label="loc_ftnt_ShortTermInvestmentsLineItemMember_DD4C61FD7A350FB78FC393DC6FFB5E0F" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_E1C09B89C6077C85885693DC6FFA50A2" xlink:to="loc_ftnt_ShortTermInvestmentsLineItemMember_DD4C61FD7A350FB78FC393DC6FFB5E0F" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_LongTermInvestmentsLineItemMember" xlink:label="loc_ftnt_LongTermInvestmentsLineItemMember_981A08E88DF43B6CFBFE93DC6FFB2543" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_E1C09B89C6077C85885693DC6FFA50A2" xlink:to="loc_ftnt_LongTermInvestmentsLineItemMember_981A08E88DF43B6CFBFE93DC6FFB2543" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_E901DA50F738990C85AA93DC6FFB9EBD" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_E215CD5D1C3566E60FA893DC6FF6E3AD" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_E901DA50F738990C85AA93DC6FFB9EBD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6567208F677815C53E5A93DC6FFB6A0E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_E901DA50F738990C85AA93DC6FFB9EBD" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6567208F677815C53E5A93DC6FFB6A0E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_BB07F65DF93CA20750B593DC6FFC890C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6567208F677815C53E5A93DC6FFB6A0E" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_BB07F65DF93CA20750B593DC6FFC890C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_8AE0C83A113EB652EAA093DC6FFC0603" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6567208F677815C53E5A93DC6FFB6A0E" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_8AE0C83A113EB652EAA093DC6FFC0603" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_B01091ADA4498F9D099F93DC6FFCD094" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6567208F677815C53E5A93DC6FFB6A0E" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_B01091ADA4498F9D099F93DC6FFCD094" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_BEE88162CDAE64E5740C93DC6FFC328A" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_E215CD5D1C3566E60FA893DC6FF6E3AD" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_BEE88162CDAE64E5740C93DC6FFC328A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_858CB96DF70684F61CEC93DC6FFCD3A3" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_BEE88162CDAE64E5740C93DC6FFC328A" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_858CB96DF70684F61CEC93DC6FFCD3A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_16117F983CD396480B7A93DC6FFD3AF0" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_BEE88162CDAE64E5740C93DC6FFC328A" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_16117F983CD396480B7A93DC6FFD3AF0" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/FinancialInstrumentsAndFairValueInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_FinancialInstrumentsAndFairValueAbstract" xlink:label="loc_ftnt_FinancialInstrumentsAndFairValueAbstract_6AFF2959DA29061F90FB93DC7008BB0E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_DF5F2F426F66C5A07E2093DC70088633" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_FinancialInstrumentsAndFairValueAbstract_6AFF2959DA29061F90FB93DC7008BB0E" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_DF5F2F426F66C5A07E2093DC70088633" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_9F1A0E04A18C9EA654C093DC700875B7" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_DF5F2F426F66C5A07E2093DC70088633" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_9F1A0E04A18C9EA654C093DC700875B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_E62173A2EAD5DC3F4F5193DC7009F419" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_9F1A0E04A18C9EA654C093DC700875B7" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_E62173A2EAD5DC3F4F5193DC7009F419" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_3380E77D745B8DF419FB93DC70099BC9" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_E62173A2EAD5DC3F4F5193DC7009F419" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_3380E77D745B8DF419FB93DC70099BC9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember" xlink:label="loc_us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_C468363F62A02F75172A93DC70092861" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_E62173A2EAD5DC3F4F5193DC7009F419" xlink:to="loc_us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_C468363F62A02F75172A93DC70092861" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_CertificatesofDepositandTermDepositsMember" xlink:label="loc_ftnt_CertificatesofDepositandTermDepositsMember_6B6B21AF9253423B42AF93E32FB8B15E" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_E62173A2EAD5DC3F4F5193DC7009F419" xlink:to="loc_ftnt_CertificatesofDepositandTermDepositsMember_6B6B21AF9253423B42AF93E32FB8B15E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_USTreasuryAndGovernmentMember" xlink:label="loc_us-gaap_USTreasuryAndGovernmentMember_4005E950E27F720225B293DC700AB8A4" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_E62173A2EAD5DC3F4F5193DC7009F419" xlink:to="loc_us-gaap_USTreasuryAndGovernmentMember_4005E950E27F720225B293DC700AB8A4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5A23193CA6149296286F93DC700A1384" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_DF5F2F426F66C5A07E2093DC70088633" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5A23193CA6149296286F93DC700A1384" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_43D81A64B62A3DD48E6A93DC700A2936" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5A23193CA6149296286F93DC700A1384" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_43D81A64B62A3DD48E6A93DC700A2936" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_88BB2FFDC4D5DB136BF693DC700A03DA" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5A23193CA6149296286F93DC700A1384" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_88BB2FFDC4D5DB136BF693DC700A03DA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_0AFAB3DB496DD20A373C93DC700A7FDF" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5A23193CA6149296286F93DC700A1384" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_0AFAB3DB496DD20A373C93DC700A7FDF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_29DA103DE4C3743378C093DC700B337E" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5A23193CA6149296286F93DC700A1384" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_29DA103DE4C3743378C093DC700B337E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract_01A660F863ED6C665D9893DC701023E1" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5A23193CA6149296286F93DC700A1384" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract_01A660F863ED6C665D9893DC701023E1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_F8607E238CE70FBD9D8993DC70100CB6" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract_01A660F863ED6C665D9893DC701023E1" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_F8607E238CE70FBD9D8993DC70100CB6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_26749A3AE7FDB4299BB593DC70102274" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract_01A660F863ED6C665D9893DC701023E1" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_26749A3AE7FDB4299BB593DC70102274" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_3680D65F49424C5E0C1993DC70109237" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract_01A660F863ED6C665D9893DC701023E1" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_3680D65F49424C5E0C1993DC70109237" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_D22A30A4D26075C8C30993DC70114760" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract_01A660F863ED6C665D9893DC701023E1" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_D22A30A4D26075C8C30993DC70114760" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue_8A51D918F149F028DAA293DC7011CD98" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract_01A660F863ED6C665D9893DC701023E1" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue_8A51D918F149F028DAA293DC7011CD98" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss_D94880BC6F798F0A2A7893DC70111844" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract_01A660F863ED6C665D9893DC701023E1" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss_D94880BC6F798F0A2A7893DC70111844" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_1E38EAEB3A4C40FDEC0593DC7011B0FE" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5A23193CA6149296286F93DC700A1384" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_1E38EAEB3A4C40FDEC0593DC7011B0FE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_3C46AB6D6B9F89D0B26F93DC7011CE49" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_1E38EAEB3A4C40FDEC0593DC7011B0FE" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_3C46AB6D6B9F89D0B26F93DC7011CE49" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_AvailableForSaleSecuritiesDebtMaturitiesAfterOneYearFairValue" xlink:label="loc_ftnt_AvailableForSaleSecuritiesDebtMaturitiesAfterOneYearFairValue_E98287CBCA40A10856F493DC701290C3" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_1E38EAEB3A4C40FDEC0593DC7011B0FE" xlink:to="loc_ftnt_AvailableForSaleSecuritiesDebtMaturitiesAfterOneYearFairValue_E98287CBCA40A10856F493DC701290C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_0F551CD50DAC58B3E5BE93DC70127409" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_1E38EAEB3A4C40FDEC0593DC7011B0FE" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_0F551CD50DAC58B3E5BE93DC70127409" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/FinancialInstrumentsAndFairValueTables" xlink:type="extended">
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_FinancialInstrumentsAndFairValueAbstract" xlink:label="loc_ftnt_FinancialInstrumentsAndFairValueAbstract_3EE85CF2218287B7B2BC6E4D05260C40" xlink:type="locator" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ScheduleOfAmortizedCostsUnrealizedGainsAndLossesAndFairValueOfAvailableForSaleSecuritiesTableTextBlock" xlink:label="loc_ftnt_ScheduleOfAmortizedCostsUnrealizedGainsAndLossesAndFairValueOfAvailableForSaleSecuritiesTableTextBlock_D1BD42ABEE81948D47D36E4D0527EB18" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_FinancialInstrumentsAndFairValueAbstract_3EE85CF2218287B7B2BC6E4D05260C40" xlink:to="loc_ftnt_ScheduleOfAmortizedCostsUnrealizedGainsAndLossesAndFairValueOfAvailableForSaleSecuritiesTableTextBlock_D1BD42ABEE81948D47D36E4D0527EB18" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock_FE2AA2F174A98C65E57B6E4D05272036" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_FinancialInstrumentsAndFairValueAbstract_3EE85CF2218287B7B2BC6E4D05260C40" xlink:to="loc_us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock_FE2AA2F174A98C65E57B6E4D05272036" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock" xlink:label="loc_us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock_FC8A3D4005B4481E785F6E4D05288FB7" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_FinancialInstrumentsAndFairValueAbstract_3EE85CF2218287B7B2BC6E4D05260C40" xlink:to="loc_us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock_FC8A3D4005B4481E785F6E4D05288FB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock_7BF0697EC286CFAAE91C6E4D05284D28" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_FinancialInstrumentsAndFairValueAbstract_3EE85CF2218287B7B2BC6E4D05260C40" xlink:to="loc_us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock_7BF0697EC286CFAAE91C6E4D05284D28" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/GoodwillAndOtherIntangibleAssetsNet" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_A6D23E27D038028A93146E4D06603A99" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock_217F751577E1CDEDD4906E4D0660AEF7" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_A6D23E27D038028A93146E4D06603A99" xlink:to="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock_217F751577E1CDEDD4906E4D0660AEF7" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/GoodwillAndOtherIntangibleAssetsNetEstimatedFutureAmortizationExpenseDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_E6B26405CCBBAED1C30D73ECD9228E19" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_505405587D98B2E796DC73ECD923AA47" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_E6B26405CCBBAED1C30D73ECD9228E19" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_505405587D98B2E796DC73ECD923AA47" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_B67C7BC00D453C3F997773ECD923BC04" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_505405587D98B2E796DC73ECD923AA47" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_B67C7BC00D453C3F997773ECD923BC04" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_FE4BBC9872F8C870FD3E73ECD92312C0" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_505405587D98B2E796DC73ECD923AA47" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_FE4BBC9872F8C870FD3E73ECD92312C0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_7879C96650E59A22D64973ECD9238A21" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_505405587D98B2E796DC73ECD923AA47" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_7879C96650E59A22D64973ECD9238A21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_242758EC36AB787C367C73ECD9230F5D" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_505405587D98B2E796DC73ECD923AA47" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_242758EC36AB787C367C73ECD9230F5D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_C0EDBBE230A3346C283273ECD9243364" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_505405587D98B2E796DC73ECD923AA47" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_C0EDBBE230A3346C283273ECD9243364" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/GoodwillAndOtherIntangibleAssetsNetNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_51A29CDE4B7DD20047CC73ECD934422B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_37C51E795E4C6719DC9273ECD936B030" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_51A29CDE4B7DD20047CC73ECD934422B" xlink:to="loc_us-gaap_Goodwill_37C51E795E4C6719DC9273ECD936B030" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillImpairmentLoss" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_A7A48FF655597B922B9373ECD93734FF" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_51A29CDE4B7DD20047CC73ECD934422B" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_A7A48FF655597B922B9373ECD93734FF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_3559BFD57A6BF8CA204F73ECD937684C" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_51A29CDE4B7DD20047CC73ECD934422B" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_3559BFD57A6BF8CA204F73ECD937684C" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/GoodwillAndOtherIntangibleAssetsNetOtherIntangibleAssetsNetDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_AB6D99AC7D50AAA663F673ECD92BC4D5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_030BCE777FB435F80A1473ECD92BA663" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_AB6D99AC7D50AAA663F673ECD92BC4D5" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_030BCE777FB435F80A1473ECD92BA663" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_AA5F41A1EB71BDF57A4673ECD92CC264" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_030BCE777FB435F80A1473ECD92BA663" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_AA5F41A1EB71BDF57A4673ECD92CC264" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_F5C96D29E2A8D8007B4E73ECD92C81F3" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_AA5F41A1EB71BDF57A4673ECD92CC264" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_F5C96D29E2A8D8007B4E73ECD92C81F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DevelopedTechnologyRightsMember" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_F1A40D7BDB3ED797CAA473ECD92D3854" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_F5C96D29E2A8D8007B4E73ECD92C81F3" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_F1A40D7BDB3ED797CAA473ECD92D3854" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="loc_us-gaap_CustomerRelationshipsMember_829F9555E2B00C5AFA0073ECD92DA8C3" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_F5C96D29E2A8D8007B4E73ECD92C81F3" xlink:to="loc_us-gaap_CustomerRelationshipsMember_829F9555E2B00C5AFA0073ECD92DA8C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_3C511CF5A852274A31ED73ECD92D983E" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_030BCE777FB435F80A1473ECD92BA663" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_3C511CF5A852274A31ED73ECD92D983E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_27447AC9653959564A8C73ECD92D7223" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_3C511CF5A852274A31ED73ECD92D983E" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_27447AC9653959564A8C73ECD92D7223" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNetAbstract" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_74545E6CE38736B6EDB973ECD92EEA2C" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_3C511CF5A852274A31ED73ECD92D983E" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_74545E6CE38736B6EDB973ECD92EEA2C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_7BA8991BE8CFBE7982FA73ECD92E3170" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_74545E6CE38736B6EDB973ECD92EEA2C" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_7BA8991BE8CFBE7982FA73ECD92E3170" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_E697EAD29F4AE640761673ECD92EF330" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_74545E6CE38736B6EDB973ECD92EEA2C" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_E697EAD29F4AE640761673ECD92EF330" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_520CC15D44B0D455CF4A73ECD92E38CB" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_74545E6CE38736B6EDB973ECD92EEA2C" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_520CC15D44B0D455CF4A73ECD92E38CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_280F1DD8956E5EC2E20773ECD92FDF5E" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_3C511CF5A852274A31ED73ECD92D983E" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_280F1DD8956E5EC2E20773ECD92FDF5E" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/GoodwillAndOtherIntangibleAssetsNetTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_EDF53CD3A6765AA1AC1873ECD93E13CE" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_E7A7D9D4E41069281D6273ECD93E2B33" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_EDF53CD3A6765AA1AC1873ECD93E13CE" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_E7A7D9D4E41069281D6273ECD93E2B33" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:label="loc_us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock_7FEF45F4E9485F559E1573ECD93E84FA" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_EDF53CD3A6765AA1AC1873ECD93E13CE" xlink:to="loc_us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock_7FEF45F4E9485F559E1573ECD93E84FA" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/IncomeTaxes" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="loc_us-gaap_IncomeTaxDisclosureAbstract_24EA4FE84B2A10ED2D146E4D02EE8600" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxDisclosureTextBlock" xlink:label="loc_us-gaap_IncomeTaxDisclosureTextBlock_6595672E2A8A478971396E4D02EFAFE7" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_24EA4FE84B2A10ED2D146E4D02EE8600" xlink:to="loc_us-gaap_IncomeTaxDisclosureTextBlock_6595672E2A8A478971396E4D02EFAFE7" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/IncomeTaxesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="loc_us-gaap_IncomeTaxDisclosureAbstract_ABA3E1EB04932CCE718E74E2977BF0FE" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_713E0B0AC24EABB94FA074E2977B6557" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_ABA3E1EB04932CCE718E74E2977BF0FE" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_713E0B0AC24EABB94FA074E2977B6557" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_EffectiveIncomeTaxRateReconciliationatFederalStatutoryIncomeTaxRateStateandLocalIncomeTaxesandForeignIncomeTaxRateDifferentialAmount" xlink:label="loc_ftnt_EffectiveIncomeTaxRateReconciliationatFederalStatutoryIncomeTaxRateStateandLocalIncomeTaxesandForeignIncomeTaxRateDifferentialAmount_12F6AF3A7906CA159DD574E2977B7D0D" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_ABA3E1EB04932CCE718E74E2977BF0FE" xlink:to="loc_ftnt_EffectiveIncomeTaxRateReconciliationatFederalStatutoryIncomeTaxRateStateandLocalIncomeTaxesandForeignIncomeTaxRateDifferentialAmount_12F6AF3A7906CA159DD574E2977B7D0D" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_EffectiveIncomeTaxReconciliationExcessTaxBenefitonStockbasedCompensation" xlink:label="loc_ftnt_EffectiveIncomeTaxReconciliationExcessTaxBenefitonStockbasedCompensation_C15C46EBDDDFB6D9EB2B74E2977B736E" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_ABA3E1EB04932CCE718E74E2977BF0FE" xlink:to="loc_ftnt_EffectiveIncomeTaxReconciliationExcessTaxBenefitonStockbasedCompensation_C15C46EBDDDFB6D9EB2B74E2977B736E" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_EffectiveIncomeTaxReconciliationUnrecognizedTaxBenefits" xlink:label="loc_ftnt_EffectiveIncomeTaxReconciliationUnrecognizedTaxBenefits_75958A16B3E2FE7ACCB574E2977CA546" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_ABA3E1EB04932CCE718E74E2977BF0FE" xlink:to="loc_ftnt_EffectiveIncomeTaxReconciliationUnrecognizedTaxBenefits_75958A16B3E2FE7ACCB574E2977CA546" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnrecognizedTaxBenefits" xlink:label="loc_us-gaap_UnrecognizedTaxBenefits_F8D9144565EF49BC07A974E2977CCE2B" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_ABA3E1EB04932CCE718E74E2977BF0FE" xlink:to="loc_us-gaap_UnrecognizedTaxBenefits_F8D9144565EF49BC07A974E2977CCE2B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate_83B587BC9F704E5FA80874E2977C0683" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_ABA3E1EB04932CCE718E74E2977BF0FE" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate_83B587BC9F704E5FA80874E2977C0683" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_A5C149B9FB15026A25EE74E2977CB1D0" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_ABA3E1EB04932CCE718E74E2977BF0FE" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_A5C149B9FB15026A25EE74E2977CB1D0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit" xlink:label="loc_us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit_FDE2A230B603608EC01C74E2977C2686" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_ABA3E1EB04932CCE718E74E2977BF0FE" xlink:to="loc_us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit_FDE2A230B603608EC01C74E2977C2686" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/Inventory" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryDisclosureAbstract" xlink:label="loc_us-gaap_InventoryDisclosureAbstract_7A866EAC7071638FADED6E4D026440FA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryDisclosureTextBlock" xlink:label="loc_us-gaap_InventoryDisclosureTextBlock_84211CCE60DDFCB261F36E4D0265AEFD" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_7A866EAC7071638FADED6E4D026440FA" xlink:to="loc_us-gaap_InventoryDisclosureTextBlock_84211CCE60DDFCB261F36E4D0265AEFD" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/InventoryDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryDisclosureAbstract" xlink:label="loc_us-gaap_InventoryDisclosureAbstract_D7F08F832285F0C6B01C73ECD99A1DFA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNetAbstract" xlink:label="loc_us-gaap_InventoryNetAbstract_4A702DCE64FD04C604BF73ECD99B2C1A" xlink:type="locator" />
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_D7F08F832285F0C6B01C73ECD99A1DFA" xlink:to="loc_us-gaap_InventoryNetAbstract_4A702DCE64FD04C604BF73ECD99B2C1A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryRawMaterialsNetOfReserves" xlink:label="loc_us-gaap_InventoryRawMaterialsNetOfReserves_79C96C382094D022C04773ECD99C0EFB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryNetAbstract_4A702DCE64FD04C604BF73ECD99B2C1A" xlink:to="loc_us-gaap_InventoryRawMaterialsNetOfReserves_79C96C382094D022C04773ECD99C0EFB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryFinishedGoodsNetOfReserves" xlink:label="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_A68908E3F5A3AC8FCEBA73ECD99C12FC" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryNetAbstract_4A702DCE64FD04C604BF73ECD99B2C1A" xlink:to="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_A68908E3F5A3AC8FCEBA73ECD99C12FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_E7A7C44396FBEA80288073ECD99CFA30" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryNetAbstract_4A702DCE64FD04C604BF73ECD99B2C1A" xlink:to="loc_us-gaap_InventoryNet_E7A7C44396FBEA80288073ECD99CFA30" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/InventoryTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryDisclosureAbstract" xlink:label="loc_us-gaap_InventoryDisclosureAbstract_AC4D8F2F32B3962F21C26E4D03F6F93B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfInventoryCurrentTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfInventoryCurrentTableTextBlock_00AA076467DE71967C8E6E4D03F6BB2A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InventoryDisclosureAbstract_AC4D8F2F32B3962F21C26E4D03F6F93B" xlink:to="loc_us-gaap_ScheduleOfInventoryCurrentTableTextBlock_00AA076467DE71967C8E6E4D03F6BB2A" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/InvestmentsInPrivatelyHeldCompanies" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentsAllOtherInvestmentsAbstract" xlink:label="loc_us-gaap_InvestmentsAllOtherInvestmentsAbstract_0919E89DED54C8BFE5368F3B8A13B202" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentTextBlock" xlink:label="loc_invest_InvestmentTextBlock_583D3B0655DDB70C5ED48F6AF185EA19" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InvestmentsAllOtherInvestmentsAbstract_0919E89DED54C8BFE5368F3B8A13B202" xlink:to="loc_invest_InvestmentTextBlock_583D3B0655DDB70C5ED48F6AF185EA19" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/InvestmentsInPrivatelyHeldCompaniesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentsAllOtherInvestmentsAbstract" xlink:label="loc_us-gaap_InvestmentsAllOtherInvestmentsAbstract_5E4AFDF5FB4C1F91138973ECD9564875" xlink:type="locator" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_EquitySecuritieswithoutReadilyDeterminableFairValueAmount" xlink:label="loc_ftnt_EquitySecuritieswithoutReadilyDeterminableFairValueAmount_FDDB58E72E02341EF84673ECD9560475" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InvestmentsAllOtherInvestmentsAbstract_5E4AFDF5FB4C1F91138973ECD9564875" xlink:to="loc_ftnt_EquitySecuritieswithoutReadilyDeterminableFairValueAmount_FDDB58E72E02341EF84673ECD9560475" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/Leases" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="loc_us-gaap_LeasesAbstract_655F2B007FF3B1A237AC73F234F5A809" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeOperatingLeasesTextBlock" xlink:label="loc_us-gaap_LesseeOperatingLeasesTextBlock_59CD3B3402071D3351E9741E78D5C863" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_655F2B007FF3B1A237AC73F234F5A809" xlink:to="loc_us-gaap_LesseeOperatingLeasesTextBlock_59CD3B3402071D3351E9741E78D5C863" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/LeasesComponentsOfLeaseExpenseDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="loc_us-gaap_LeasesAbstract_99177305A3492A2DA23D74253D9FBFCB" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeaseCost" xlink:label="loc_us-gaap_OperatingLeaseCost_3F36BF22551E271A6DEC7462BB8742D5" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_99177305A3492A2DA23D74253D9FBFCB" xlink:to="loc_us-gaap_OperatingLeaseCost_3F36BF22551E271A6DEC7462BB8742D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableLeaseCost" xlink:label="loc_us-gaap_VariableLeaseCost_218638B513965310EB857462D536C119" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_99177305A3492A2DA23D74253D9FBFCB" xlink:to="loc_us-gaap_VariableLeaseCost_218638B513965310EB857462D536C119" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShortTermLeaseCost" xlink:label="loc_us-gaap_ShortTermLeaseCost_0A8DD3BBFB574998A4BE7462FC69E3FA" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_99177305A3492A2DA23D74253D9FBFCB" xlink:to="loc_us-gaap_ShortTermLeaseCost_0A8DD3BBFB574998A4BE7462FC69E3FA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeaseCost" xlink:label="loc_us-gaap_LeaseCost_56C982D060D5B33EFCFD7463288F46D1" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_99177305A3492A2DA23D74253D9FBFCB" xlink:to="loc_us-gaap_LeaseCost_56C982D060D5B33EFCFD7463288F46D1" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/LeasesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="loc_us-gaap_LeasesAbstract_26B6B97A4157BD25F2D58DFFAF61A78E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_94F7DA103CB24EBB79E48DFFAF62B6F7" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_26B6B97A4157BD25F2D58DFFAF61A78E" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_94F7DA103CB24EBB79E48DFFAF62B6F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_5E10C84D5FC706EE05818DFFAF62A803" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_94F7DA103CB24EBB79E48DFFAF62B6F7" xlink:to="loc_us-gaap_RangeAxis_5E10C84D5FC706EE05818DFFAF62A803" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_F97A7864BD8E231FAB7F8DFFAF62E3DC" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeAxis_5E10C84D5FC706EE05818DFFAF62A803" xlink:to="loc_us-gaap_RangeMember_F97A7864BD8E231FAB7F8DFFAF62E3DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_0FDAEF025E6EF931566A8DFFAF62BF4F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_F97A7864BD8E231FAB7F8DFFAF62E3DC" xlink:to="loc_us-gaap_MinimumMember_0FDAEF025E6EF931566A8DFFAF62BF4F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_67886D74EC56109641438DFFAF63D535" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_F97A7864BD8E231FAB7F8DFFAF62E3DC" xlink:to="loc_us-gaap_MaximumMember_67886D74EC56109641438DFFAF63D535" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_3AE051ACCACB4E13D3ED8DFFAF6312E7" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_94F7DA103CB24EBB79E48DFFAF62B6F7" xlink:to="loc_us-gaap_LesseeLeaseDescriptionLineItems_3AE051ACCACB4E13D3ED8DFFAF6312E7" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_OperatingLeaseRemainingLeaseTerm" xlink:label="loc_ftnt_OperatingLeaseRemainingLeaseTerm_77ABE0ECD4F85235627B8E0F96F9556E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_3AE051ACCACB4E13D3ED8DFFAF6312E7" xlink:to="loc_ftnt_OperatingLeaseRemainingLeaseTerm_77ABE0ECD4F85235627B8E0F96F9556E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm" xlink:label="loc_us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm_933CBFDB4B2029C8E9F18DFFAF6415DE" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_3AE051ACCACB4E13D3ED8DFFAF6312E7" xlink:to="loc_us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm_933CBFDB4B2029C8E9F18DFFAF6415DE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesRentExpenseNet" xlink:label="loc_us-gaap_OperatingLeasesRentExpenseNet_6A5C6E1837B53BBB85658DFFAF643385" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_3AE051ACCACB4E13D3ED8DFFAF6312E7" xlink:to="loc_us-gaap_OperatingLeasesRentExpenseNet_6A5C6E1837B53BBB85658DFFAF643385" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_OperatingLeaseLeaseNotyetCommencedExpense" xlink:label="loc_ftnt_OperatingLeaseLeaseNotyetCommencedExpense_2B857749748AF52D1D3D8DFFAF64F157" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_3AE051ACCACB4E13D3ED8DFFAF6312E7" xlink:to="loc_ftnt_OperatingLeaseLeaseNotyetCommencedExpense_2B857749748AF52D1D3D8DFFAF64F157" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract" xlink:label="loc_us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract_6CB4FD28BA1BB97A68FC8DFFAF64A376" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_3AE051ACCACB4E13D3ED8DFFAF6312E7" xlink:to="loc_us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract_6CB4FD28BA1BB97A68FC8DFFAF64A376" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/LeasesFuturePrincipalContractualObligationsForOperatingLeaseCommitmentsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="loc_us-gaap_LeasesAbstract_7F8A26A547D449C8F764744552D2ABB1" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_D0878DFCF7795D7C2D637470E3514980" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_7F8A26A547D449C8F764744552D2ABB1" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_D0878DFCF7795D7C2D637470E3514980" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_95C4076CDB05238F5A777470F25AF48A" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_7F8A26A547D449C8F764744552D2ABB1" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_95C4076CDB05238F5A777470F25AF48A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_35C198C8B19F42DE6DB37471004A6555" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_7F8A26A547D449C8F764744552D2ABB1" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_35C198C8B19F42DE6DB37471004A6555" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_40EAF76516984B2923E5747110E47A34" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_7F8A26A547D449C8F764744552D2ABB1" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_40EAF76516984B2923E5747110E47A34" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_44EEB927F27EBCEB94F674711FDE0FEB" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_7F8A26A547D449C8F764744552D2ABB1" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_44EEB927F27EBCEB94F674711FDE0FEB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_4D20B220C39509E660B074712ED95C52" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_7F8A26A547D449C8F764744552D2ABB1" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_4D20B220C39509E660B074712ED95C52" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_DF96752F1B9A718D94FC74713ECA4532" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_7F8A26A547D449C8F764744552D2ABB1" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_DF96752F1B9A718D94FC74713ECA4532" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/LeasesMaturitiesOfOperatingLeaseLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="loc_us-gaap_LeasesAbstract_09EFB4C34A3CA5B6AEE37A6C0DB47279" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_E1E390AFFF59C8F556DB7A6C0DB4E394" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_09EFB4C34A3CA5B6AEE37A6C0DB47279" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_E1E390AFFF59C8F556DB7A6C0DB4E394" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_64FA744C75BEF25FB2E17A6C0DB57E83" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_09EFB4C34A3CA5B6AEE37A6C0DB47279" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_64FA744C75BEF25FB2E17A6C0DB57E83" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_AF212E68B1E87DE7C3B97A6C0DB57507" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_09EFB4C34A3CA5B6AEE37A6C0DB47279" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_AF212E68B1E87DE7C3B97A6C0DB57507" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_3686CA344A7A043CB47E7A6C0DB5EF52" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_09EFB4C34A3CA5B6AEE37A6C0DB47279" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_3686CA344A7A043CB47E7A6C0DB5EF52" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_D98983C2544FF7218C1A7A6C0DB54092" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_09EFB4C34A3CA5B6AEE37A6C0DB47279" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_D98983C2544FF7218C1A7A6C0DB54092" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_E94B133AAC5DB386EC467A6C0DB541FC" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_09EFB4C34A3CA5B6AEE37A6C0DB47279" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_E94B133AAC5DB386EC467A6C0DB541FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_B4E6DBEFB20D958234FE7A6C0DB5121F" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_09EFB4C34A3CA5B6AEE37A6C0DB47279" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_B4E6DBEFB20D958234FE7A6C0DB5121F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_D3EE564B4B05302B476A7A6C0DB5DE05" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_09EFB4C34A3CA5B6AEE37A6C0DB47279" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_D3EE564B4B05302B476A7A6C0DB5DE05" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeaseLiability" xlink:label="loc_us-gaap_OperatingLeaseLiability_9A7C1436E9808663BBA97A6C0DB6D26C" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_09EFB4C34A3CA5B6AEE37A6C0DB47279" xlink:to="loc_us-gaap_OperatingLeaseLiability_9A7C1436E9808663BBA97A6C0DB6D26C" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/LeasesSupplementalBalanceSheetInformationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="loc_us-gaap_LeasesAbstract_2FB5C2AE6D519FDD7B1A8DFFAF4E1BAE" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_44EEC32C8C4B61CBD63A8DFFAF4E48FA" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_2FB5C2AE6D519FDD7B1A8DFFAF4E1BAE" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_44EEC32C8C4B61CBD63A8DFFAF4E48FA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_0EB7890873954214E0D58DFFAF4E6E77" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_2FB5C2AE6D519FDD7B1A8DFFAF4E1BAE" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_0EB7890873954214E0D58DFFAF4E6E77" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_C3D047D67DFB87BE2C498DFFAF4F21FE" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_2FB5C2AE6D519FDD7B1A8DFFAF4E1BAE" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_C3D047D67DFB87BE2C498DFFAF4F21FE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeaseLiability" xlink:label="loc_us-gaap_OperatingLeaseLiability_E38BD1050886B6A374768DFFAF4FD7E2" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_2FB5C2AE6D519FDD7B1A8DFFAF4E1BAE" xlink:to="loc_us-gaap_OperatingLeaseLiability_E38BD1050886B6A374768DFFAF4FD7E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm_2D2D046F7E5E5749B7838DFFAF4FD93F" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_2FB5C2AE6D519FDD7B1A8DFFAF4E1BAE" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm_2D2D046F7E5E5749B7838DFFAF4FD93F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_015A5E72C834733FF0CE8DFFAF4F0AA3" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_2FB5C2AE6D519FDD7B1A8DFFAF4E1BAE" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_015A5E72C834733FF0CE8DFFAF4F0AA3" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/LeasesSupplementalCashFlowInformationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="loc_us-gaap_LeasesAbstract_5996B6B53B3F978F0133743395A0E72C" xlink:type="locator" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_CashFlowLesseeAbstract" xlink:label="loc_ftnt_CashFlowLesseeAbstract_EF584687995BF140B0147467C886AF51" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_5996B6B53B3F978F0133743395A0E72C" xlink:to="loc_ftnt_CashFlowLesseeAbstract_EF584687995BF140B0147467C886AF51" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasePayments" xlink:label="loc_us-gaap_OperatingLeasePayments_41576BBA16ABD911EFA77468745584B9" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_CashFlowLesseeAbstract_EF584687995BF140B0147467C886AF51" xlink:to="loc_us-gaap_OperatingLeasePayments_41576BBA16ABD911EFA77468745584B9" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_LeaseLiabilitiesArisingfromObtainingRightofUseAssetsAbstract" xlink:label="loc_ftnt_LeaseLiabilitiesArisingfromObtainingRightofUseAssetsAbstract_03FC290C499476C1F8157468F3A95CF4" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_5996B6B53B3F978F0133743395A0E72C" xlink:to="loc_ftnt_LeaseLiabilitiesArisingfromObtainingRightofUseAssetsAbstract_03FC290C499476C1F8157468F3A95CF4" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_LeaseLiabilityArisingfromObtainingRightofUseAsset" xlink:label="loc_ftnt_LeaseLiabilityArisingfromObtainingRightofUseAsset_967EB3DAED91F513A143746A16EFA8B6" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_LeaseLiabilitiesArisingfromObtainingRightofUseAssetsAbstract_03FC290C499476C1F8157468F3A95CF4" xlink:to="loc_ftnt_LeaseLiabilityArisingfromObtainingRightofUseAsset_967EB3DAED91F513A143746A16EFA8B6" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/LeasesTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="loc_us-gaap_LeasesAbstract_B882B8CB80511726D37D8DFFAF6DBAFD" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeaseCostTableTextBlock" xlink:label="loc_us-gaap_LeaseCostTableTextBlock_59200B9266CAC4BF903D8DFFAF6D8818" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_B882B8CB80511726D37D8DFFAF6DBAFD" xlink:to="loc_us-gaap_LeaseCostTableTextBlock_59200B9266CAC4BF903D8DFFAF6D8818" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_AssetsAndLiabilitiesLesseeTableTextBlock" xlink:label="loc_ftnt_AssetsAndLiabilitiesLesseeTableTextBlock_B38EFE17BDBD787795DB8DFFAF6D4845" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_B882B8CB80511726D37D8DFFAF6DBAFD" xlink:to="loc_ftnt_AssetsAndLiabilitiesLesseeTableTextBlock_B38EFE17BDBD787795DB8DFFAF6D4845" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_C149762A06A08BC0100E8DFFAF6DC9F5" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_B882B8CB80511726D37D8DFFAF6DBAFD" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_C149762A06A08BC0100E8DFFAF6DC9F5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock_B1201A8D7D612785AFBD8E11A17072EF" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_B882B8CB80511726D37D8DFFAF6DBAFD" xlink:to="loc_us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock_B1201A8D7D612785AFBD8E11A17072EF" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/NetIncomePerShare" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract_57EF9FEB37F820CC76F26E4D036368B6" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareTextBlock" xlink:label="loc_us-gaap_EarningsPerShareTextBlock_21918D819663B410E11A6E4D0363C63D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_57EF9FEB37F820CC76F26E4D036368B6" xlink:to="loc_us-gaap_EarningsPerShareTextBlock_21918D819663B410E11A6E4D0363C63D" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/NetIncomePerShareAntiDilutiveSecuritiesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract_A53D61110FA47D09588B6E4D05756231" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_8757A5D41039A86A4F966E4D0576FAD3" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_A53D61110FA47D09588B6E4D05756231" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_8757A5D41039A86A4F966E4D0576FAD3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_728734590BE2C1DCADDF6E4D0577C461" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_8757A5D41039A86A4F966E4D0576FAD3" xlink:to="loc_us-gaap_AwardTypeAxis_728734590BE2C1DCADDF6E4D0577C461" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5D7EB19B79D7CCFE3CC96E4D05778EA1" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_728734590BE2C1DCADDF6E4D0577C461" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5D7EB19B79D7CCFE3CC96E4D05778EA1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_286226C62818DFDA5FDC6E4D05773BEF" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5D7EB19B79D7CCFE3CC96E4D05778EA1" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_286226C62818DFDA5FDC6E4D05773BEF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_E0745C40B1918CF497FC6E4D0578EC68" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5D7EB19B79D7CCFE3CC96E4D05778EA1" xlink:to="loc_us-gaap_EmployeeStockOptionMember_E0745C40B1918CF497FC6E4D0578EC68" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockMember" xlink:label="loc_us-gaap_EmployeeStockMember_BD39C0059F9E54295F9D6E4D05780C8C" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5D7EB19B79D7CCFE3CC96E4D05778EA1" xlink:to="loc_us-gaap_EmployeeStockMember_BD39C0059F9E54295F9D6E4D05780C8C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_F065A0482A344EFEBDFE6E4D0579074C" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_8757A5D41039A86A4F966E4D0576FAD3" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_F065A0482A344EFEBDFE6E4D0579074C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_D13019229C530552A8766E4D0579B1DC" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_F065A0482A344EFEBDFE6E4D0579074C" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_D13019229C530552A8766E4D0579B1DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockCompensationPlanMember" xlink:label="loc_us-gaap_StockCompensationPlanMember_28EDA58F7E43DF8239336E4D057956E1" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_D13019229C530552A8766E4D0579B1DC" xlink:to="loc_us-gaap_StockCompensationPlanMember_28EDA58F7E43DF8239336E4D057956E1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_64ED2E2D277A22DACFF86E4D057A98B9" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_8757A5D41039A86A4F966E4D0576FAD3" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_64ED2E2D277A22DACFF86E4D057A98B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_D4B38C9E95C16BCB2F726E4D057A2F8F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_64ED2E2D277A22DACFF86E4D057A98B9" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_D4B38C9E95C16BCB2F726E4D057A2F8F" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/NetIncomePerShareCalculationOfBasicAndDilutedDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract_6E94F53D3580592756926E4D02546A4A" xlink:type="locator" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ScheduleOfEarningsPerShareTable" xlink:label="loc_ftnt_ScheduleOfEarningsPerShareTable_AE7579B76359404C3BBA6E4D025576EC" xlink:type="locator" />
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_6E94F53D3580592756926E4D02546A4A" xlink:to="loc_ftnt_ScheduleOfEarningsPerShareTable_AE7579B76359404C3BBA6E4D025576EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_F146C4ED886ED8400EF46E4D0255D475" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_ScheduleOfEarningsPerShareTable_AE7579B76359404C3BBA6E4D025576EC" xlink:to="loc_us-gaap_AwardTypeAxis_F146C4ED886ED8400EF46E4D0255D475" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_34560B1CBCA3944EB4046E4D02557360" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_F146C4ED886ED8400EF46E4D0255D475" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_34560B1CBCA3944EB4046E4D02557360" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_528683C932890E674BC66E4D0256ED3F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_34560B1CBCA3944EB4046E4D02557360" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_528683C932890E674BC66E4D0256ED3F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_9CCBBCFA92F55E47332E6E4D02561C8D" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_34560B1CBCA3944EB4046E4D02557360" xlink:to="loc_us-gaap_EmployeeStockOptionMember_9CCBBCFA92F55E47332E6E4D02561C8D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockMember" xlink:label="loc_us-gaap_EmployeeStockMember_FC39E324C00D334377CB6E4D0256099A" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_34560B1CBCA3944EB4046E4D02557360" xlink:to="loc_us-gaap_EmployeeStockMember_FC39E324C00D334377CB6E4D0256099A" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_EarningsPerShareLineItems" xlink:label="loc_ftnt_EarningsPerShareLineItems_22F530189B27220118FE6E4D025663A7" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_ScheduleOfEarningsPerShareTable_AE7579B76359404C3BBA6E4D025576EC" xlink:to="loc_ftnt_EarningsPerShareLineItems_22F530189B27220118FE6E4D025663A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_4644F0C8FC02B0DB170A6E4D0257BE91" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_EarningsPerShareLineItems_22F530189B27220118FE6E4D025663A7" xlink:to="loc_us-gaap_NetIncomeLoss_4644F0C8FC02B0DB170A6E4D0257BE91" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract_0168537BE4FDADD45B396E4D02572E4F" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_EarningsPerShareLineItems_22F530189B27220118FE6E4D025663A7" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract_0168537BE4FDADD45B396E4D02572E4F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_DA8E06712F8BF7AF4E1D6E4D02586EB1" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract_0168537BE4FDADD45B396E4D02572E4F" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_DA8E06712F8BF7AF4E1D6E4D02586EB1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_FBC5525F5139B8D9CDA16E4D025879E1" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_EarningsPerShareLineItems_22F530189B27220118FE6E4D025663A7" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_FBC5525F5139B8D9CDA16E4D025879E1" xlink:type="arc" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_FBC5525F5139B8D9CDA16E4D025879E1" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_DA8E06712F8BF7AF4E1D6E4D02586EB1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract" xlink:label="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract_60225BF8AE3D338BED756E4D0259688B" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_EarningsPerShareLineItems_22F530189B27220118FE6E4D025663A7" xlink:to="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract_60225BF8AE3D338BED756E4D0259688B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_EE927E90D7F3F318E8F66E4D02593426" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract_60225BF8AE3D338BED756E4D0259688B" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_EE927E90D7F3F318E8F66E4D02593426" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_F21CBD9553E21884717A6E4D02598CA9" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustmentAbstract_60225BF8AE3D338BED756E4D0259688B" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_F21CBD9553E21884717A6E4D02598CA9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="loc_us-gaap_EarningsPerShareBasic_2B0FBD49E71AFD6181526E4D02594CEC" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_EarningsPerShareLineItems_22F530189B27220118FE6E4D025663A7" xlink:to="loc_us-gaap_EarningsPerShareBasic_2B0FBD49E71AFD6181526E4D02594CEC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="loc_us-gaap_EarningsPerShareDiluted_12D31B1AA92B8FE37EF36E4D0259B3C6" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_EarningsPerShareLineItems_22F530189B27220118FE6E4D025663A7" xlink:to="loc_us-gaap_EarningsPerShareDiluted_12D31B1AA92B8FE37EF36E4D0259B3C6" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/NetIncomePerShareTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract_E3FD81BD3B3E23300F756E4D03E7CE05" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_EDF667E69AAD263F30936E4D03E81A2C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_E3FD81BD3B3E23300F756E4D03E7CE05" xlink:to="loc_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_EDF667E69AAD263F30936E4D03E81A2C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock_B9CFFE74AE7B7E6A7FC66E4D03E8E077" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_E3FD81BD3B3E23300F756E4D03E7CE05" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock_B9CFFE74AE7B7E6A7FC66E4D03E8E077" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/PropertyAndEquipmentnet" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_7AD00537EB1916F5CD226E4D0268A75D" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_195F7C997E968DBA83926E4D02699B4D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_7AD00537EB1916F5CD226E4D0268A75D" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_195F7C997E968DBA83926E4D02699B4D" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/PropertyAndEquipmentnetDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_93ACFBE8C4797CBCC70174E298801304" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_3566661CBEE05A43D7FC74E298811ACB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_93ACFBE8C4797CBCC70174E298801304" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_3566661CBEE05A43D7FC74E298811ACB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_7CA979ADBBDE50658A5274E29881F732" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_3566661CBEE05A43D7FC74E298811ACB" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_7CA979ADBBDE50658A5274E29881F732" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9CB691E6639CABA49FB674E298811F4D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_7CA979ADBBDE50658A5274E29881F732" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9CB691E6639CABA49FB674E298811F4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LandMember" xlink:label="loc_us-gaap_LandMember_93240E8AD7A09D178A5374E29881F679" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9CB691E6639CABA49FB674E298811F4D" xlink:to="loc_us-gaap_LandMember_93240E8AD7A09D178A5374E29881F679" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_0F70450836E5FA24FE8C74E29882C629" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9CB691E6639CABA49FB674E298811F4D" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_0F70450836E5FA24FE8C74E29882C629" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComputerEquipmentMember" xlink:label="loc_us-gaap_ComputerEquipmentMember_D738D2D8AFBDF14471B574E2988211CA" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9CB691E6639CABA49FB674E298811F4D" xlink:to="loc_us-gaap_ComputerEquipmentMember_D738D2D8AFBDF14471B574E2988211CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LeaseholdsAndLeaseholdImprovementsMember" xlink:label="loc_us-gaap_LeaseholdsAndLeaseholdImprovementsMember_CC4D2F8ABDCB413248A774E298828C9B" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9CB691E6639CABA49FB674E298811F4D" xlink:to="loc_us-gaap_LeaseholdsAndLeaseholdImprovementsMember_CC4D2F8ABDCB413248A774E298828C9B" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_EvaluationUnitsMember" xlink:label="loc_ftnt_EvaluationUnitsMember_110CAC8F8424EB1D898274E29882CDC1" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9CB691E6639CABA49FB674E298811F4D" xlink:to="loc_ftnt_EvaluationUnitsMember_110CAC8F8424EB1D898274E29882CDC1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_15021F8A7D50F49993DC74E29882DE14" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9CB691E6639CABA49FB674E298811F4D" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_15021F8A7D50F49993DC74E29882DE14" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConstructionInProgressMember" xlink:label="loc_us-gaap_ConstructionInProgressMember_F98031E058BAC511D64574E298823E33" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9CB691E6639CABA49FB674E298811F4D" xlink:to="loc_us-gaap_ConstructionInProgressMember_F98031E058BAC511D64574E298823E33" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_7DE69869CF923C61F16A74E29883B62C" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_3566661CBEE05A43D7FC74E298811ACB" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentLineItems_7DE69869CF923C61F16A74E29883B62C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNetByTypeAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNetByTypeAbstract_96A977E7318312127C4274E298835D9F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_7DE69869CF923C61F16A74E29883B62C" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNetByTypeAbstract_96A977E7318312127C4274E298835D9F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_E8E7600A39819559EAD674E29883CE8D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetByTypeAbstract_96A977E7318312127C4274E298835D9F" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_E8E7600A39819559EAD674E29883CE8D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_2CF53EEDA1E148DB1CBF74E29883BAE5" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetByTypeAbstract_96A977E7318312127C4274E298835D9F" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_2CF53EEDA1E148DB1CBF74E29883BAE5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_D6A3F582436FAB7F659874E298842EFA" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNetByTypeAbstract_96A977E7318312127C4274E298835D9F" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_D6A3F582436FAB7F659874E298842EFA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Depreciation" xlink:label="loc_us-gaap_Depreciation_A50D49B3B1B32BFD094C74E2988402ED" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_7DE69869CF923C61F16A74E29883B62C" xlink:to="loc_us-gaap_Depreciation_A50D49B3B1B32BFD094C74E2988402ED" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/PropertyAndEquipmentnetTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_7B09E48980C6A07D17A26E4D029CFE83" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTextBlock_4C147E21D2EF706E5E3E6E4D029CF6A0" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_7B09E48980C6A07D17A26E4D029CFE83" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTextBlock_4C147E21D2EF706E5E3E6E4D029CF6A0" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/RevenueRecognition" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract_B0B6E6B5A80F7064E58A6E4D04AD9BCA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerTextBlock_9CD4670ECE23B565C2D26E4D04ADDC8B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_B0B6E6B5A80F7064E58A6E4D04AD9BCA" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerTextBlock_9CD4670ECE23B565C2D26E4D04ADDC8B" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/RevenueRecognitionDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract_9229E76A8CAABC0501CD7A6C0E595C97" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_5CF00FE4339B8CE72E5E7A6C0E59B569" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_9229E76A8CAABC0501CD7A6C0E595C97" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_5CF00FE4339B8CE72E5E7A6C0E59B569" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_A558AEF87548DB5639957A6C0E599874" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_5CF00FE4339B8CE72E5E7A6C0E59B569" xlink:to="loc_us-gaap_RangeAxis_A558AEF87548DB5639957A6C0E599874" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_AA7432CE153AD688F4BB7A6C0E5974E9" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeAxis_A558AEF87548DB5639957A6C0E599874" xlink:to="loc_us-gaap_RangeMember_AA7432CE153AD688F4BB7A6C0E5974E9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_5F1FD7B2ED2F538A44147A6C0E5A60C2" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_AA7432CE153AD688F4BB7A6C0E5974E9" xlink:to="loc_us-gaap_MinimumMember_5F1FD7B2ED2F538A44147A6C0E5A60C2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_B29D5DBAB36F3A63B4F37A6C0E5A01DA" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_AA7432CE153AD688F4BB7A6C0E5974E9" xlink:to="loc_us-gaap_MaximumMember_B29D5DBAB36F3A63B4F37A6C0E5A01DA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_1BC2EAD814CF395F962A7A6C0E5B7CAC" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_5CF00FE4339B8CE72E5E7A6C0E59B569" xlink:to="loc_us-gaap_DisaggregationOfRevenueLineItems_1BC2EAD814CF395F962A7A6C0E5B7CAC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_BC85EE2763DF6DAF2CAD7A6C0E5BC923" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_1BC2EAD814CF395F962A7A6C0E5B7CAC" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_BC85EE2763DF6DAF2CAD7A6C0E5BC923" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_RevenueRecognitionPeriod" xlink:label="loc_ftnt_RevenueRecognitionPeriod_59123F690ACAD9B09D187A6C0E5BAD9C" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_1BC2EAD814CF395F962A7A6C0E5B7CAC" xlink:to="loc_ftnt_RevenueRecognitionPeriod_59123F690ACAD9B09D187A6C0E5BAD9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_380DE4E6DD92F51755837A6C0E5BA962" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_1BC2EAD814CF395F962A7A6C0E5B7CAC" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_380DE4E6DD92F51755837A6C0E5BA962" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalizedContractCostAmortization" xlink:label="loc_us-gaap_CapitalizedContractCostAmortization_036296115B4E88D9C0B57A6C0E5C03D1" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_1BC2EAD814CF395F962A7A6C0E5B7CAC" xlink:to="loc_us-gaap_CapitalizedContractCostAmortization_036296115B4E88D9C0B57A6C0E5C03D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalizedContractCostImpairmentLoss" xlink:label="loc_us-gaap_CapitalizedContractCostImpairmentLoss_4B763264A8E57C3921EC7A6C0E5CD52A" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_1BC2EAD814CF395F962A7A6C0E5B7CAC" xlink:to="loc_us-gaap_CapitalizedContractCostImpairmentLoss_4B763264A8E57C3921EC7A6C0E5CD52A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_C2DF2420E457F58DE7597A6C0E5C21C7" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_1BC2EAD814CF395F962A7A6C0E5B7CAC" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_C2DF2420E457F58DE7597A6C0E5C21C7" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/RevenueRecognitionDisaggregatedRevenuesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract_EADA6EB0755CC6E6DBF393DC52A0A5CA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_D896C630B0BCF21251AE93DC52A03F16" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_EADA6EB0755CC6E6DBF393DC52A0A5CA" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_D896C630B0BCF21251AE93DC52A03F16" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="loc_us-gaap_ProductOrServiceAxis_5E8DD9C6BE15B7EF3FF393DC52A06168" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_D896C630B0BCF21251AE93DC52A03F16" xlink:to="loc_us-gaap_ProductOrServiceAxis_5E8DD9C6BE15B7EF3FF393DC52A06168" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_6281D301FAD0A8D8760593DC52A16A12" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductOrServiceAxis_5E8DD9C6BE15B7EF3FF393DC52A06168" xlink:to="loc_us-gaap_ProductsAndServicesDomain_6281D301FAD0A8D8760593DC52A16A12" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductMember" xlink:label="loc_us-gaap_ProductMember_C69F6A7CBF32EFF7411093DC52A1A72B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_6281D301FAD0A8D8760593DC52A16A12" xlink:to="loc_us-gaap_ProductMember_C69F6A7CBF32EFF7411093DC52A1A72B" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ServiceMember" xlink:label="loc_ftnt_ServiceMember_C9FFBE97FA6DC588B46A93DC52A1490B" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ProductsAndServicesDomain_6281D301FAD0A8D8760593DC52A16A12" xlink:to="loc_ftnt_ServiceMember_C9FFBE97FA6DC588B46A93DC52A1490B" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_SecuritySubscriptionMember" xlink:label="loc_ftnt_SecuritySubscriptionMember_2600A7CC21260619BB9893DC52A196E4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_ServiceMember_C9FFBE97FA6DC588B46A93DC52A1490B" xlink:to="loc_ftnt_SecuritySubscriptionMember_2600A7CC21260619BB9893DC52A196E4" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_TechnicalSupportandOtherMember" xlink:label="loc_ftnt_TechnicalSupportandOtherMember_796AAB9DD8AA8ED45C2593DDAFCE29EC" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ftnt_ServiceMember_C9FFBE97FA6DC588B46A93DC52A1490B" xlink:to="loc_ftnt_TechnicalSupportandOtherMember_796AAB9DD8AA8ED45C2593DDAFCE29EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_99C55BD9F1943ACAC61293DC52A2E634" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_D896C630B0BCF21251AE93DC52A03F16" xlink:to="loc_us-gaap_DisaggregationOfRevenueLineItems_99C55BD9F1943ACAC61293DC52A2E634" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_B3A05D4E17F53EC42D6C93DC52A29396" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_99C55BD9F1943ACAC61293DC52A2E634" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_B3A05D4E17F53EC42D6C93DC52A29396" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/RevenueRecognitionPerformanceObligationSatisfactionPeriodDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract_69082F9BDE7FE32C833D8FC31021694A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_40DAE745F874EF546B2A8FC31022D9E2" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_69082F9BDE7FE32C833D8FC31021694A" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_40DAE745F874EF546B2A8FC31022D9E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_951AC3750AB0A410FC178FC31022F029" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_40DAE745F874EF546B2A8FC31022D9E2" xlink:to="loc_us-gaap_RangeAxis_951AC3750AB0A410FC178FC31022F029" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_7BA346C79323636CC10C8FC3102206FC" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeAxis_951AC3750AB0A410FC178FC31022F029" xlink:to="loc_us-gaap_RangeMember_7BA346C79323636CC10C8FC3102206FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_C7A77EDB8DE5B6E680B28FC310225D85" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_7BA346C79323636CC10C8FC3102206FC" xlink:to="loc_us-gaap_MaximumMember_C7A77EDB8DE5B6E680B28FC310225D85" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_8BE7D43FCDF652695C8E8FC31023855A" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_7BA346C79323636CC10C8FC3102206FC" xlink:to="loc_us-gaap_MinimumMember_8BE7D43FCDF652695C8E8FC31023855A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_15E1435203A5A84269E88FC310238CE0" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_40DAE745F874EF546B2A8FC31022D9E2" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_15E1435203A5A84269E88FC310238CE0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_380237AEA8AA01E16D888FC31023F24C" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_40DAE745F874EF546B2A8FC31022D9E2" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_380237AEA8AA01E16D888FC31023F24C" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_RevenueRemainingPerformanceObligationPercentage" xlink:label="loc_ftnt_RevenueRemainingPerformanceObligationPercentage_1DC3E94D77728D7B7D848FC49D0E9B98" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_380237AEA8AA01E16D888FC31023F24C" xlink:to="loc_ftnt_RevenueRemainingPerformanceObligationPercentage_1DC3E94D77728D7B7D848FC49D0E9B98" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod_F47AB71631CC3BFD5FD88FC310241160" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_380237AEA8AA01E16D888FC31023F24C" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod_F47AB71631CC3BFD5FD88FC310241160" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_RevenueRecognitionPeriod" xlink:label="loc_ftnt_RevenueRecognitionPeriod_5D3AF9151A8C26C2140F8FC310244F74" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_380237AEA8AA01E16D888FC31023F24C" xlink:to="loc_ftnt_RevenueRecognitionPeriod_5D3AF9151A8C26C2140F8FC310244F74" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/RevenueRecognitionTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract_7B3129E3E487B5534833751AB2575A5B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:label="loc_us-gaap_DisaggregationOfRevenueTableTextBlock_A53E1343F2FEC7DFC2AB751AB257853F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_7B3129E3E487B5534833751AB2575A5B" xlink:to="loc_us-gaap_DisaggregationOfRevenueTableTextBlock_A53E1343F2FEC7DFC2AB751AB257853F" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/SegmentInformation" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingAbstract" xlink:label="loc_us-gaap_SegmentReportingAbstract_561663C0087EB0EB466A6E4D02E5D4AF" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingDisclosureTextBlock" xlink:label="loc_us-gaap_SegmentReportingDisclosureTextBlock_F2D190C0ADA432550CD86E4D02E5D066" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingAbstract_561663C0087EB0EB466A6E4D02E5D4AF" xlink:to="loc_us-gaap_SegmentReportingDisclosureTextBlock_F2D190C0ADA432550CD86E4D02E5D066" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/SegmentInformationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingAbstract" xlink:label="loc_us-gaap_SegmentReportingAbstract_8E1A238088779A5E779F93DC6E562D4A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9558481357A5441EAC9F93DC6E5640A8" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingAbstract_8E1A238088779A5E779F93DC6E562D4A" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9558481357A5441EAC9F93DC6E5640A8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="loc_us-gaap_StatementGeographicalAxis_4838159AC58A44A6768B93DC6E5698C6" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9558481357A5441EAC9F93DC6E5640A8" xlink:to="loc_us-gaap_StatementGeographicalAxis_4838159AC58A44A6768B93DC6E5698C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_CC34D4FA91597A72C52D93DC6E56FC54" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementGeographicalAxis_4838159AC58A44A6768B93DC6E5698C6" xlink:to="loc_us-gaap_SegmentGeographicalDomain_CC34D4FA91597A72C52D93DC6E56FC54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AmericasMember" xlink:label="loc_us-gaap_AmericasMember_9FBD35B99D7B03A1D26993DC6E57EBE6" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentGeographicalDomain_CC34D4FA91597A72C52D93DC6E56FC54" xlink:to="loc_us-gaap_AmericasMember_9FBD35B99D7B03A1D26993DC6E57EBE6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_US" xlink:label="loc_country_US_763086B3B0FA24DBF27593DC6E5779BB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AmericasMember_9FBD35B99D7B03A1D26993DC6E57EBE6" xlink:to="loc_country_US_763086B3B0FA24DBF27593DC6E5779BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_CA" xlink:label="loc_country_CA_6CD30B7719DEDE93E06493DC6E573ABA" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AmericasMember_9FBD35B99D7B03A1D26993DC6E57EBE6" xlink:to="loc_country_CA_6CD30B7719DEDE93E06493DC6E573ABA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LatinAmericaMember" xlink:label="loc_us-gaap_LatinAmericaMember_CF8E614B0BCE7BAE2FAD93DC6E57BBD1" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AmericasMember_9FBD35B99D7B03A1D26993DC6E57EBE6" xlink:to="loc_us-gaap_LatinAmericaMember_CF8E614B0BCE7BAE2FAD93DC6E57BBD1" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_OtherAmericasMember" xlink:label="loc_ftnt_OtherAmericasMember_82957D01ED15F7DDC02F93DC6E582C73" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AmericasMember_9FBD35B99D7B03A1D26993DC6E57EBE6" xlink:to="loc_ftnt_OtherAmericasMember_82957D01ED15F7DDC02F93DC6E582C73" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_EuropeMiddleEastAndAfricaMember" xlink:label="loc_ftnt_EuropeMiddleEastAndAfricaMember_9F2561DCBB22A5D0DBE993DC6E58707D" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentGeographicalDomain_CC34D4FA91597A72C52D93DC6E56FC54" xlink:to="loc_ftnt_EuropeMiddleEastAndAfricaMember_9F2561DCBB22A5D0DBE993DC6E58707D" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_AsiaPacificAndJapanMember" xlink:label="loc_ftnt_AsiaPacificAndJapanMember_F62CFC1BD09DE9786D1693DC6E5866AA" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentGeographicalDomain_CC34D4FA91597A72C52D93DC6E56FC54" xlink:to="loc_ftnt_AsiaPacificAndJapanMember_F62CFC1BD09DE9786D1693DC6E5866AA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="loc_us-gaap_MajorCustomersAxis_7D972922979BF0C43AA093DC6E585C05" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9558481357A5441EAC9F93DC6E5640A8" xlink:to="loc_us-gaap_MajorCustomersAxis_7D972922979BF0C43AA093DC6E585C05" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="loc_us-gaap_NameOfMajorCustomerDomain_E7265A0B4668A4CAFAAA93DC6E58F892" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_MajorCustomersAxis_7D972922979BF0C43AA093DC6E585C05" xlink:to="loc_us-gaap_NameOfMajorCustomerDomain_E7265A0B4668A4CAFAAA93DC6E58F892" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ExclusiveNetworksGroupMember" xlink:label="loc_ftnt_ExclusiveNetworksGroupMember_85B3590DD5AA63CDA1CF93DC6E598C22" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_E7265A0B4668A4CAFAAA93DC6E58F892" xlink:to="loc_ftnt_ExclusiveNetworksGroupMember_85B3590DD5AA63CDA1CF93DC6E598C22" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_IngramMicroMember" xlink:label="loc_ftnt_IngramMicroMember_ABE10A93403E00D846B893DC6E59C236" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_E7265A0B4668A4CAFAAA93DC6E58F892" xlink:to="loc_ftnt_IngramMicroMember_ABE10A93403E00D846B893DC6E59C236" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_4D2291075EE3D985C43B93DC6E59B384" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9558481357A5441EAC9F93DC6E5640A8" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_4D2291075EE3D985C43B93DC6E59B384" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_46771D0D25E0FE9DB65D93DC6E594DC3" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_4D2291075EE3D985C43B93DC6E59B384" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_46771D0D25E0FE9DB65D93DC6E594DC3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_1A323E619B59D2AA8D7193DC6E5AA260" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_46771D0D25E0FE9DB65D93DC6E594DC3" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_1A323E619B59D2AA8D7193DC6E5AA260" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_BB449F49172B5C30E24A93DC6E5A79D6" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9558481357A5441EAC9F93DC6E5640A8" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_BB449F49172B5C30E24A93DC6E5A79D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_A1038FE9F4B8FF40AB0193DC6E5A03C1" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_BB449F49172B5C30E24A93DC6E5A79D6" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_A1038FE9F4B8FF40AB0193DC6E5A03C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SalesRevenueNetMember" xlink:label="loc_us-gaap_SalesRevenueNetMember_97DDDB77AB514A702E9B93DC6E5AE55F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_A1038FE9F4B8FF40AB0193DC6E5A03C1" xlink:to="loc_us-gaap_SalesRevenueNetMember_97DDDB77AB514A702E9B93DC6E5AE55F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableMember" xlink:label="loc_us-gaap_AccountsReceivableMember_9F39D04AAAEFD270D8C593DC6E5A1099" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_A1038FE9F4B8FF40AB0193DC6E5A03C1" xlink:to="loc_us-gaap_AccountsReceivableMember_9F39D04AAAEFD270D8C593DC6E5A1099" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_912077456C565E854C0593DC6E5B7DB2" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9558481357A5441EAC9F93DC6E5640A8" xlink:to="loc_us-gaap_SegmentReportingInformationLineItems_912077456C565E854C0593DC6E5B7DB2" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_NumberOfBusinessActivities" xlink:label="loc_ftnt_NumberOfBusinessActivities_EF64A5E49A37D1A699DB93DC6E5B7304" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_912077456C565E854C0593DC6E5B7DB2" xlink:to="loc_ftnt_NumberOfBusinessActivities_EF64A5E49A37D1A699DB93DC6E5B7304" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_NumberOfSegmentManagersResponsibleForOperations" xlink:label="loc_ftnt_NumberOfSegmentManagersResponsibleForOperations_170133CC1EA7E34901FB93DC6E5BB508" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_912077456C565E854C0593DC6E5B7DB2" xlink:to="loc_ftnt_NumberOfSegmentManagersResponsibleForOperations_170133CC1EA7E34901FB93DC6E5BB508" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NumberOfOperatingSegments" xlink:label="loc_us-gaap_NumberOfOperatingSegments_A8D8AE3D7A2CB4837BDD93DC6E5B3099" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_912077456C565E854C0593DC6E5B7DB2" xlink:to="loc_us-gaap_NumberOfOperatingSegments_A8D8AE3D7A2CB4837BDD93DC6E5B3099" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:label="loc_us-gaap_NumberOfReportableSegments_C1DAC3903034D53A2CA093DC6E5B9793" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_912077456C565E854C0593DC6E5B7DB2" xlink:to="loc_us-gaap_NumberOfReportableSegments_C1DAC3903034D53A2CA093DC6E5B9793" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_B8C12B3A3C5D85B7F87893DC6E5C27C6" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_912077456C565E854C0593DC6E5B7DB2" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_B8C12B3A3C5D85B7F87893DC6E5C27C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_AF55811DC547491B132293DC6E5CF477" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_912077456C565E854C0593DC6E5B7DB2" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_AF55811DC547491B132293DC6E5CF477" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_7F6FA3AF7B34E5C45FD893DC6E5CA38D" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_912077456C565E854C0593DC6E5B7DB2" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_7F6FA3AF7B34E5C45FD893DC6E5CA38D" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/SegmentInformationTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingAbstract" xlink:label="loc_us-gaap_SegmentReportingAbstract_2163B7537BFA41D63A756E4D029410BC" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenueFromExternalCustomersByGeographicAreasTableTextBlock" xlink:label="loc_us-gaap_RevenueFromExternalCustomersByGeographicAreasTableTextBlock_7F9B8FDE570F7DE6D2796E4D02944C54" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingAbstract_2163B7537BFA41D63A756E4D029410BC" xlink:to="loc_us-gaap_RevenueFromExternalCustomersByGeographicAreasTableTextBlock_7F9B8FDE570F7DE6D2796E4D02944C54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongLivedAssetsByGeographicAreasTableTextBlock" xlink:label="loc_us-gaap_LongLivedAssetsByGeographicAreasTableTextBlock_B822DA91BA3D62AAE3576E4D02948116" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingAbstract_2163B7537BFA41D63A756E4D029410BC" xlink:to="loc_us-gaap_LongLivedAssetsByGeographicAreasTableTextBlock_B822DA91BA3D62AAE3576E4D02948116" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SchedulesOfConcentrationOfRiskByRiskFactorTextBlock" xlink:label="loc_us-gaap_SchedulesOfConcentrationOfRiskByRiskFactorTextBlock_A130A1AC379F8FB46DFC6E4D02949BD3" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SegmentReportingAbstract_2163B7537BFA41D63A756E4D029410BC" xlink:to="loc_us-gaap_SchedulesOfConcentrationOfRiskByRiskFactorTextBlock_A130A1AC379F8FB46DFC6E4D02949BD3" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/StockholdersEquity" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_D93E1E430026D201404273ECD8EAD8FC" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_B7A05597335941B197F773ECD8EA951F" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_D93E1E430026D201404273ECD8EAD8FC" xlink:to="loc_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_B7A05597335941B197F773ECD8EA951F" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/StockholdersEquityAllocationOfStockBasedCompensationExpenseDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_D18D97E7DEE145FAB0D074E2979DCFEE" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_C912BCD6ED637345BF9074E2979D8E37" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_D18D97E7DEE145FAB0D074E2979DCFEE" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_C912BCD6ED637345BF9074E2979D8E37" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_4CC7091910B2733CF6BC74E2979E1BE6" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_C912BCD6ED637345BF9074E2979D8E37" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_4CC7091910B2733CF6BC74E2979E1BE6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_7E6C7398748E550E6A2374E2979FB276" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_4CC7091910B2733CF6BC74E2979E1BE6" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_7E6C7398748E550E6A2374E2979FB276" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_CostOfGoodsSoldMember" xlink:label="loc_ftnt_CostOfGoodsSoldMember_C6118A3CFB320E8412A174E2979F2431" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_7E6C7398748E550E6A2374E2979FB276" xlink:to="loc_ftnt_CostOfGoodsSoldMember_C6118A3CFB320E8412A174E2979F2431" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_CostOfServicesMember" xlink:label="loc_ftnt_CostOfServicesMember_F595A7B0B4F47897F74374E2979FA2DC" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_7E6C7398748E550E6A2374E2979FB276" xlink:to="loc_ftnt_CostOfServicesMember_F595A7B0B4F47897F74374E2979FA2DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_225EE658FC3CBBF1ED9474E2979FD3A0" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_7E6C7398748E550E6A2374E2979FB276" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_225EE658FC3CBBF1ED9474E2979FD3A0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SellingAndMarketingExpenseMember" xlink:label="loc_us-gaap_SellingAndMarketingExpenseMember_76B0AB45AFB10C116AA474E2979F0E83" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_7E6C7398748E550E6A2374E2979FB276" xlink:to="loc_us-gaap_SellingAndMarketingExpenseMember_76B0AB45AFB10C116AA474E2979F0E83" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_4B2229B0CF5C5B86366374E297A0CFAB" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_7E6C7398748E550E6A2374E2979FB276" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_4B2229B0CF5C5B86366374E297A0CFAB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_DC1C81653484616C6E9474E2979DBDA3" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_C912BCD6ED637345BF9074E2979D8E37" xlink:to="loc_us-gaap_AwardTypeAxis_DC1C81653484616C6E9474E2979DBDA3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0486850E58DEE9C53FDA74E2979D3039" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_DC1C81653484616C6E9474E2979DBDA3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0486850E58DEE9C53FDA74E2979D3039" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_CCE2FE6C492CF329031974E2979ECFD7" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0486850E58DEE9C53FDA74E2979D3039" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_CCE2FE6C492CF329031974E2979ECFD7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_50F21E7EF92EC35A0DD374E2979E3BD9" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0486850E58DEE9C53FDA74E2979D3039" xlink:to="loc_us-gaap_EmployeeStockOptionMember_50F21E7EF92EC35A0DD374E2979E3BD9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockMember" xlink:label="loc_us-gaap_EmployeeStockMember_5AD8F509F279EC20B72474E2979E193F" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0486850E58DEE9C53FDA74E2979D3039" xlink:to="loc_us-gaap_EmployeeStockMember_5AD8F509F279EC20B72474E2979E193F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_76D3E20E0E34E41C158D74E297A0196C" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_C912BCD6ED637345BF9074E2979D8E37" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_76D3E20E0E34E41C158D74E297A0196C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_E13677683E460441AA4374E297A0C9C4" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_76D3E20E0E34E41C158D74E297A0196C" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_E13677683E460441AA4374E297A0C9C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions_E781F032BD6330EFB46174E297A019DE" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_76D3E20E0E34E41C158D74E297A0196C" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions_E781F032BD6330EFB46174E297A019DE" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/StockholdersEquityDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_2E072F6BDBFC00C9272974E297D221EC" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6C9B68C645F6A7AF4EDF74E297D330DC" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_2E072F6BDBFC00C9272974E297D221EC" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6C9B68C645F6A7AF4EDF74E297D330DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_C9A56950C5D0D9A24BF474E297D4610B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6C9B68C645F6A7AF4EDF74E297D330DC" xlink:to="loc_us-gaap_RangeAxis_C9A56950C5D0D9A24BF474E297D4610B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_95BD0A8C49709B6B4C0D74E297D5BFA6" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeAxis_C9A56950C5D0D9A24BF474E297D4610B" xlink:to="loc_us-gaap_RangeMember_95BD0A8C49709B6B4C0D74E297D5BFA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_28F421C6124CC8EA0EB374E297D5B466" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_95BD0A8C49709B6B4C0D74E297D5BFA6" xlink:to="loc_us-gaap_MinimumMember_28F421C6124CC8EA0EB374E297D5B466" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_A449644F2C8CF74ABDBE74E297D52A3E" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RangeMember_95BD0A8C49709B6B4C0D74E297D5BFA6" xlink:to="loc_us-gaap_MaximumMember_A449644F2C8CF74ABDBE74E297D52A3E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_04DE68FA749078E9A84974E297D7BFE6" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6C9B68C645F6A7AF4EDF74E297D330DC" xlink:to="loc_us-gaap_AwardTypeAxis_04DE68FA749078E9A84974E297D7BFE6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ADC48B28B4FB7352545C74E297D7ECE3" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_04DE68FA749078E9A84974E297D7BFE6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ADC48B28B4FB7352545C74E297D7ECE3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockCompensationPlanMember" xlink:label="loc_us-gaap_StockCompensationPlanMember_F3284240804CD4A03FE474E297D84B9D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ADC48B28B4FB7352545C74E297D7ECE3" xlink:to="loc_us-gaap_StockCompensationPlanMember_F3284240804CD4A03FE474E297D84B9D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_5E4FF9590D27FFCA90EA74E297D7C162" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ADC48B28B4FB7352545C74E297D7ECE3" xlink:to="loc_us-gaap_EmployeeStockOptionMember_5E4FF9590D27FFCA90EA74E297D7C162" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeStockMember" xlink:label="loc_us-gaap_EmployeeStockMember_070BC0A7197F76C1928E74E297D851C4" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ADC48B28B4FB7352545C74E297D7ECE3" xlink:to="loc_us-gaap_EmployeeStockMember_070BC0A7197F76C1928E74E297D851C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis" xlink:label="loc_us-gaap_ShareRepurchaseProgramAxis_AE0AC08658D7238A347874E297D39E5E" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6C9B68C645F6A7AF4EDF74E297D330DC" xlink:to="loc_us-gaap_ShareRepurchaseProgramAxis_AE0AC08658D7238A347874E297D39E5E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_8A7EB07EBF522A94D76B74E297D3ACED" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_AE0AC08658D7238A347874E297D39E5E" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_8A7EB07EBF522A94D76B74E297D3ACED" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ShareRepurchaseProgramMember" xlink:label="loc_ftnt_ShareRepurchaseProgramMember_26D239863D317D4C463D74E297D45B4C" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareRepurchaseProgramDomain_8A7EB07EBF522A94D76B74E297D3ACED" xlink:to="loc_ftnt_ShareRepurchaseProgramMember_26D239863D317D4C463D74E297D45B4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6C9B68C645F6A7AF4EDF74E297D330DC" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_6392839C75551C6F464974E297D8CC8A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_6392839C75551C6F464974E297D8CC8A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_8A99D13D14B2F22E8E8874E297D8903F" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_8A99D13D14B2F22E8E8874E297D8903F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_CED8228B0C1CBF0DB38A74E297D981BB" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_CED8228B0C1CBF0DB38A74E297D981BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_04115A1A5107E236FF1374E297D9A9C0" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_CED8228B0C1CBF0DB38A74E297D981BB" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_04115A1A5107E236FF1374E297D9A9C0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_81DEEACC79686CF2D60974E297D9BD57" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_CED8228B0C1CBF0DB38A74E297D981BB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_81DEEACC79686CF2D60974E297D9BD57" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_A5DEF5980F81C8A17C7D74E297D9B8CE" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_CED8228B0C1CBF0DB38A74E297D981BB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_A5DEF5980F81C8A17C7D74E297D9B8CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_9CF25055836A8DC716A874E297D950A5" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_CED8228B0C1CBF0DB38A74E297D981BB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_9CF25055836A8DC716A874E297D950A5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_145ED9EA58A3061E3F7774E297D94B3B" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_145ED9EA58A3061E3F7774E297D94B3B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_EBA3A274A93634DCF0D174E297DA4E63" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_145ED9EA58A3061E3F7774E297D94B3B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_EBA3A274A93634DCF0D174E297DA4E63" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_38EFAEEBE82E50C5F95074E297DA4C98" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_145ED9EA58A3061E3F7774E297D94B3B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_38EFAEEBE82E50C5F95074E297DA4C98" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_5F2093694FFF5BBB343174E297DAEDD9" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_145ED9EA58A3061E3F7774E297D94B3B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_5F2093694FFF5BBB343174E297DAEDD9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_D6DB5BF3970C6551DE2474E297DA9516" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_145ED9EA58A3061E3F7774E297D94B3B" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_D6DB5BF3970C6551DE2474E297DA9516" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_B932A9CB4C5F32922D3A74E297DAF0AA" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_145ED9EA58A3061E3F7774E297D94B3B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_B932A9CB4C5F32922D3A74E297DAF0AA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_9B25EA63F28A9B43F04F74E297DB71B9" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_9B25EA63F28A9B43F04F74E297DB71B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_D639CD3262EBF7F8BD4E74E297DBE48B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_9B25EA63F28A9B43F04F74E297DB71B9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_D639CD3262EBF7F8BD4E74E297DBE48B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_01D28538E30FEBEE933D74E297DBA901" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_9B25EA63F28A9B43F04F74E297DB71B9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_01D28538E30FEBEE933D74E297DBA901" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_1DE0166CADB559F38C8B74E297DC259A" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_9B25EA63F28A9B43F04F74E297DB71B9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_1DE0166CADB559F38C8B74E297DC259A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_AAFD2C47EA356074597E74E297DCFDC6" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_9B25EA63F28A9B43F04F74E297DB71B9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_AAFD2C47EA356074597E74E297DCFDC6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_BAFC5519BF1ABA6980C274E297DC2C09" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_9B25EA63F28A9B43F04F74E297DB71B9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_BAFC5519BF1ABA6980C274E297DC2C09" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_BF8C20840810F401EE4F74E297DC7170" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_BF8C20840810F401EE4F74E297DC7170" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_E46CBC7BC8DEE5AB2FDE74E297DC041A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_BF8C20840810F401EE4F74E297DC7170" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_E46CBC7BC8DEE5AB2FDE74E297DC041A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_0F3EB47C3B9179C379C874E297DDD22B" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_BF8C20840810F401EE4F74E297DC7170" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_0F3EB47C3B9179C379C874E297DDD22B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_2C9A247AC0B363E73BEB74E297DD4813" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_BF8C20840810F401EE4F74E297DC7170" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_2C9A247AC0B363E73BEB74E297DD4813" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_A2BD755449A7DFF0ADAB74E297DD7226" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_BF8C20840810F401EE4F74E297DC7170" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_A2BD755449A7DFF0ADAB74E297DD7226" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_550E7500894C0D07BFDB74E297DDA3BE" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_BF8C20840810F401EE4F74E297DC7170" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_550E7500894C0D07BFDB74E297DDA3BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_056BA70658B7335F60D174E297DE001F" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_BF8C20840810F401EE4F74E297DC7170" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_056BA70658B7335F60D174E297DE001F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_49CFBA2B32EC75BB01F074E297DEF72E" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_BF8C20840810F401EE4F74E297DC7170" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_49CFBA2B32EC75BB01F074E297DEF72E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_9B816C071553379CAEC274E297DE8689" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_BF8C20840810F401EE4F74E297DC7170" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_9B816C071553379CAEC274E297DE8689" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_09B8E740C8BC9A6924BA74E297DE8E79" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_09B8E740C8BC9A6924BA74E297DE8E79" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_F4F80C7EC6DEFE4F2E7C74E297DE974C" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_F4F80C7EC6DEFE4F2E7C74E297DE974C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_57A1900D69EBD9AF968F74E297DF23DE" xlink:type="locator" />
    <link:presentationArc order="9" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_57A1900D69EBD9AF968F74E297DF23DE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_F1C3A15D06C332D611C574E297DF1F3A" xlink:type="locator" />
    <link:presentationArc order="10" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_F1C3A15D06C332D611C574E297DF1F3A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1_AE4CA7D82AC6EDCD54B774E297DF36DA" xlink:type="locator" />
    <link:presentationArc order="11" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_63A142C0177DC6D09BF674E297D8EE94" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1_AE4CA7D82AC6EDCD54B774E297DF36DA" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/StockholdersEquityRestrictedStockUnitsActivityDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_B71B5E609724347640BF74E297C3DDF5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4329C532056C37BBFB3F74E297C3850E" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_B71B5E609724347640BF74E297C3DDF5" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4329C532056C37BBFB3F74E297C3850E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_9ABE36052FFCFA650E3774E297C3FB35" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4329C532056C37BBFB3F74E297C3850E" xlink:to="loc_us-gaap_AwardTypeAxis_9ABE36052FFCFA650E3774E297C3FB35" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_063E1D4DE25BCED9BA9474E297C33C94" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_9ABE36052FFCFA650E3774E297C3FB35" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_063E1D4DE25BCED9BA9474E297C33C94" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_D909EB6E3952AAF2058E74E297C45960" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_063E1D4DE25BCED9BA9474E297C33C94" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_D909EB6E3952AAF2058E74E297C45960" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CA3B62B4F86E3DB2993974E297C40053" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4329C532056C37BBFB3F74E297C3850E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CA3B62B4F86E3DB2993974E297C40053" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_289287AF84E2E9724BF674E297C46BD8" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CA3B62B4F86E3DB2993974E297C40053" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_289287AF84E2E9724BF674E297C46BD8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_5DAF9ED3C3314C2FAC2074E297C5792D" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_289287AF84E2E9724BF674E297C46BD8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_5DAF9ED3C3314C2FAC2074E297C5792D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_D855905CD22E8995784574E297C5DE27" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_289287AF84E2E9724BF674E297C46BD8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_D855905CD22E8995784574E297C5DE27" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_F8F8BE8C2BCA9C3F8A6174E297C5661C" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_289287AF84E2E9724BF674E297C46BD8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_F8F8BE8C2BCA9C3F8A6174E297C5661C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_78CF88E7172D0EBA280E74E297C51119" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_289287AF84E2E9724BF674E297C46BD8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_78CF88E7172D0EBA280E74E297C51119" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_E3EF45683D00A51E6C8674E297C52217" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_289287AF84E2E9724BF674E297C46BD8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_E3EF45683D00A51E6C8674E297C52217" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_0E487117C107F9D7E83C74E297C5373A" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CA3B62B4F86E3DB2993974E297C40053" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_0E487117C107F9D7E83C74E297C5373A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_C527273BCEB65DA45A0D74E297C6CDE3" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_0E487117C107F9D7E83C74E297C5373A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_C527273BCEB65DA45A0D74E297C6CDE3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_66EC8AE388A1443CEDC274E297C6CB1B" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_0E487117C107F9D7E83C74E297C5373A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_66EC8AE388A1443CEDC274E297C6CB1B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_E412B2AED392AC99A7AB74E297C61BBE" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_0E487117C107F9D7E83C74E297C5373A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_E412B2AED392AC99A7AB74E297C61BBE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_460DD2B9BCEFC0C63FC574E297C602D4" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_0E487117C107F9D7E83C74E297C5373A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_460DD2B9BCEFC0C63FC574E297C602D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_4A7EA1008A9C4C676D9374E297C6C509" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_0E487117C107F9D7E83C74E297C5373A" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_4A7EA1008A9C4C676D9374E297C6C509" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_D2F9548D45A7D8694F1374E297C734C3" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CA3B62B4F86E3DB2993974E297C40053" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_D2F9548D45A7D8694F1374E297C734C3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_3F4B95A2EC3289D3195074E297C70EF8" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CA3B62B4F86E3DB2993974E297C40053" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_3F4B95A2EC3289D3195074E297C70EF8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_7395D486ACD9D0A0A11274E297C7C073" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CA3B62B4F86E3DB2993974E297C40053" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_7395D486ACD9D0A0A11274E297C7C073" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_F4547FBC61B26806CE1874E297C79D22" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_CA3B62B4F86E3DB2993974E297C40053" xlink:to="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_F4547FBC61B26806CE1874E297C79D22" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/StockholdersEquityShareRepurchaseProgramDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_5EC63D06B6AEF3DF653693A77BBC33E0" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_347513E9467F1A2038B293A77BBC4811" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_5EC63D06B6AEF3DF653693A77BBC33E0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_347513E9467F1A2038B293A77BBC4811" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis" xlink:label="loc_us-gaap_ShareRepurchaseProgramAxis_90EDEC6DCFF505DACD6A93A77BBC7D3A" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_347513E9467F1A2038B293A77BBC4811" xlink:to="loc_us-gaap_ShareRepurchaseProgramAxis_90EDEC6DCFF505DACD6A93A77BBC7D3A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_75F42AE38E1C270A187C93A77BBCC310" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_90EDEC6DCFF505DACD6A93A77BBC7D3A" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_75F42AE38E1C270A187C93A77BBCC310" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ShareRepurchaseProgramMember" xlink:label="loc_ftnt_ShareRepurchaseProgramMember_13A39577DE4AB5ABFF8B93A77BBC2FB6" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareRepurchaseProgramDomain_75F42AE38E1C270A187C93A77BBCC310" xlink:to="loc_ftnt_ShareRepurchaseProgramMember_13A39577DE4AB5ABFF8B93A77BBC2FB6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_618CD32BBA8595CAEDB993A77BBCE6F8" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_347513E9467F1A2038B293A77BBC4811" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_618CD32BBA8595CAEDB993A77BBCE6F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:label="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_308E3FC718DCB7D231A693A77BBC0DDB" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_618CD32BBA8595CAEDB993A77BBCE6F8" xlink:to="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_308E3FC718DCB7D231A693A77BBC0DDB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_582F7958A9D6E3CDC52D93A77BCCAA59" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_618CD32BBA8595CAEDB993A77BBCE6F8" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_582F7958A9D6E3CDC52D93A77BCCAA59" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TreasuryStockAcquiredAverageCostPerShare" xlink:label="loc_us-gaap_TreasuryStockAcquiredAverageCostPerShare_878F43B589EC3EA8C74D93A77BCCA620" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_618CD32BBA8595CAEDB993A77BBCE6F8" xlink:to="loc_us-gaap_TreasuryStockAcquiredAverageCostPerShare_878F43B589EC3EA8C74D93A77BCCA620" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_08E61E4EFC4313B4109D93A77BCC0213" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_618CD32BBA8595CAEDB993A77BBCE6F8" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_08E61E4EFC4313B4109D93A77BCC0213" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_F9F1149C7AA29EF5BA1093A77BCC6438" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_618CD32BBA8595CAEDB993A77BBCE6F8" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_F9F1149C7AA29EF5BA1093A77BCC6438" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/StockholdersEquityTables" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_5F28F18A7FA0F1060A08751AB12A5D4B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock_49723871EDCBDF387CC3751AB12A3FAA" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_5F28F18A7FA0F1060A08751AB12A5D4B" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock_49723871EDCBDF387CC3751AB12A3FAA" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ScheduleofSharebasedCompensationSharesWithheldforTaxesTableTextBlock" xlink:label="loc_ftnt_ScheduleofSharebasedCompensationSharesWithheldforTaxesTableTextBlock_24B08385A330A4D437CC751AB12AE6CF" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_5F28F18A7FA0F1060A08751AB12A5D4B" xlink:to="loc_ftnt_ScheduleofSharebasedCompensationSharesWithheldforTaxesTableTextBlock_24B08385A330A4D437CC751AB12AE6CF" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsAndAllocationOfRecognizedPeriodCostsTableTextBlock" xlink:label="loc_ftnt_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsAndAllocationOfRecognizedPeriodCostsTableTextBlock_05D58B1F638190A2D0D8751AB12B7DBC" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_5F28F18A7FA0F1060A08751AB12A5D4B" xlink:to="loc_ftnt_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsAndAllocationOfRecognizedPeriodCostsTableTextBlock_05D58B1F638190A2D0D8751AB12B7DBC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_0162BA4748AA1C3BA67F751AB12B6FD2" xlink:type="locator" />
    <link:presentationArc order="4" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_5F28F18A7FA0F1060A08751AB12A5D4B" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_0162BA4748AA1C3BA67F751AB12B6FD2" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ScheduleofSharebasedCompensationStockOptionsActivityAdditionalInformationTableTextBlock" xlink:label="loc_ftnt_ScheduleofSharebasedCompensationStockOptionsActivityAdditionalInformationTableTextBlock_24322FB7649F8FB3E203751AB12B843F" xlink:type="locator" />
    <link:presentationArc order="5" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_5F28F18A7FA0F1060A08751AB12A5D4B" xlink:to="loc_ftnt_ScheduleofSharebasedCompensationStockOptionsActivityAdditionalInformationTableTextBlock_24322FB7649F8FB3E203751AB12B843F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_41EEB8F404C599E2AB25751AB12BAC8D" xlink:type="locator" />
    <link:presentationArc order="6" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_5F28F18A7FA0F1060A08751AB12A5D4B" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_41EEB8F404C599E2AB25751AB12BAC8D" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_ScheduleofEmployeeServiceSharebasedCompensationAllocationofRecognizedPeriodCostsbyAwardTypeTableTextBlock" xlink:label="loc_ftnt_ScheduleofEmployeeServiceSharebasedCompensationAllocationofRecognizedPeriodCostsbyAwardTypeTableTextBlock_F5EEA0CBE690272CC48E751AB12CF6B4" xlink:type="locator" />
    <link:presentationArc order="7" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_5F28F18A7FA0F1060A08751AB12A5D4B" xlink:to="loc_ftnt_ScheduleofEmployeeServiceSharebasedCompensationAllocationofRecognizedPeriodCostsbyAwardTypeTableTextBlock_F5EEA0CBE690272CC48E751AB12CF6B4" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_IncomeTaxBenefitFromStockOptionPlansTableTextBlock" xlink:label="loc_ftnt_IncomeTaxBenefitFromStockOptionPlansTableTextBlock_A35FBC9C6720E32E3618751AB12C8548" xlink:type="locator" />
    <link:presentationArc order="8" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_5F28F18A7FA0F1060A08751AB12A5D4B" xlink:to="loc_ftnt_IncomeTaxBenefitFromStockOptionPlansTableTextBlock_A35FBC9C6720E32E3618751AB12C8548" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/SummaryOfSignificantAccountingPolicies" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="loc_us-gaap_AccountingPoliciesAbstract_BA60EA739E003AC9736973ECDB74B19F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SignificantAccountingPoliciesTextBlock" xlink:label="loc_us-gaap_SignificantAccountingPoliciesTextBlock_85D1940ADA2AAFD39F8673ECDB748009" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_BA60EA739E003AC9736973ECDB74B19F" xlink:to="loc_us-gaap_SignificantAccountingPoliciesTextBlock_85D1940ADA2AAFD39F8673ECDB748009" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="loc_us-gaap_AccountingPoliciesAbstract_216D2EAAB5D71FCDFE0A73ECDB6CDA75" xlink:type="locator" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_PresentationAndPreparationOfConsolidatedFinancialStatementsPolicyTextBlock" xlink:label="loc_ftnt_PresentationAndPreparationOfConsolidatedFinancialStatementsPolicyTextBlock_51237B0A35E4205772FC73ECDB6CD223" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_216D2EAAB5D71FCDFE0A73ECDB6CDA75" xlink:to="loc_ftnt_PresentationAndPreparationOfConsolidatedFinancialStatementsPolicyTextBlock_51237B0A35E4205772FC73ECDB6CD223" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:label="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_EF63B3AA17FD85EB5E2D73ECDB6C919D" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_216D2EAAB5D71FCDFE0A73ECDB6CDA75" xlink:to="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_EF63B3AA17FD85EB5E2D73ECDB6C919D" xlink:type="arc" />
  </link:presentationLink>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/SummaryOfSignificantAccountingPoliciesRecentAccountingPronouncementsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="loc_us-gaap_AccountingPoliciesAbstract_EFB5F21731436CEC858A74E299122244" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NewAccountingPronouncementEarlyAdoptionTable" xlink:label="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionTable_56FFED33E02504B8972174E29912B4F8" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_EFB5F21731436CEC858A74E299122244" xlink:to="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionTable_56FFED33E02504B8972174E29912B4F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_87E043DE3991E58EEE5774E299123D2B" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionTable_56FFED33E02504B8972174E29912B4F8" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_87E043DE3991E58EEE5774E299123D2B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_042420D1D35CF9E814C474E299127914" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_87E043DE3991E58EEE5774E299123D2B" xlink:to="loc_us-gaap_EquityComponentDomain_042420D1D35CF9E814C474E299127914" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_8A2C95CF977C044B610374E29913CE22" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_042420D1D35CF9E814C474E299127914" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_8A2C95CF977C044B610374E29913CE22" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_40AFF85D4F689970DB4574E2991377BC" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_042420D1D35CF9E814C474E299127914" xlink:to="loc_us-gaap_RetainedEarningsMember_40AFF85D4F689970DB4574E2991377BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_4A7FDBBB19536F3CEC7174E299132119" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionTable_56FFED33E02504B8972174E29912B4F8" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_4A7FDBBB19536F3CEC7174E299132119" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_6B4147A2B781169D5DFC74E299140DED" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_4A7FDBBB19536F3CEC7174E299132119" xlink:to="loc_us-gaap_TypeOfAdoptionMember_6B4147A2B781169D5DFC74E299140DED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountingStandardsUpdate201602Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201602Member_245A81613B3F7F41DB6B74E299147CA5" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TypeOfAdoptionMember_6B4147A2B781169D5DFC74E299140DED" xlink:to="loc_us-gaap_AccountingStandardsUpdate201602Member_245A81613B3F7F41DB6B74E299147CA5" xlink:type="arc" />
    <link:loc xlink:href="ftnt-20190331.xsd#ftnt_AccountingStandardsUpdate201802Member" xlink:label="loc_ftnt_AccountingStandardsUpdate201802Member_CE69FAF3F4FD3189C08174E2991409CE" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TypeOfAdoptionMember_6B4147A2B781169D5DFC74E299140DED" xlink:to="loc_ftnt_AccountingStandardsUpdate201802Member_CE69FAF3F4FD3189C08174E2991409CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NewAccountingPronouncementEarlyAdoptionLineItems" xlink:label="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionLineItems_AC3E9355542FA9B5505474E299158972" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionTable_56FFED33E02504B8972174E29912B4F8" xlink:to="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionLineItems_AC3E9355542FA9B5505474E299158972" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_4F6658FE1E22B3A7E59E74E299152086" xlink:type="locator" />
    <link:presentationArc order="1" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionLineItems_AC3E9355542FA9B5505474E299158972" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_4F6658FE1E22B3A7E59E74E299152086" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeaseLiability" xlink:label="loc_us-gaap_OperatingLeaseLiability_6549D8EBCAE9D898A48F74E299152547" xlink:type="locator" />
    <link:presentationArc order="2" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionLineItems_AC3E9355542FA9B5505474E299158972" xlink:to="loc_us-gaap_OperatingLeaseLiability_6549D8EBCAE9D898A48F74E299152547" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_59C35F081DC4C36214A874E299151DEA" xlink:type="locator" />
    <link:presentationArc order="3" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NewAccountingPronouncementEarlyAdoptionLineItems_AC3E9355542FA9B5505474E299158972" xlink:to="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_59C35F081DC4C36214A874E299151DEA" xlink:type="arc" />
  </link:presentationLink>
</link:linkbase>
