<XBRL>
<xsd:schema attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.fortinet.com/20110930" xmlns:ftnt="http://www.fortinet.com/20110930" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <!--XBRL Document Created with WebFilings-->
  <xsd:import namespace="http://fasb.org/us-gaap/2011-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd" />
  <xsd:import namespace="http://fasb.org/us-roles/2011-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2011/elts/us-roles-2011-01-31.xsd" />
  <xsd:import namespace="http://fasb.org/us-types/2011-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2011/elts/us-types-2011-01-31.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2009/arcrole/fact-explanatoryFact" schemaLocation="http://www.xbrl.org/lrr/arcrole/factExplanatory-2009-12-16.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2009/role/negated" schemaLocation="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2009/role/net" schemaLocation="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd" />
  <xsd:import namespace="http://www.xbrl.org/dtr/type/non-numeric" schemaLocation="http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd" />
  <xsd:import namespace="http://www.xbrl.org/dtr/type/numeric" schemaLocation="http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd" />
  <xsd:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/country/2011-01-31" schemaLocation="http://xbrl.sec.gov/country/2011/country-2011-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/currency/2011-01-31" schemaLocation="http://xbrl.sec.gov/currency/2011/currency-2011-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/dei/2011-01-31" schemaLocation="http://xbrl.sec.gov/dei/2011/dei-2011-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/exch/2011-01-31" schemaLocation="http://xbrl.sec.gov/exch/2011/exch-2011-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/invest/2011-01-31" schemaLocation="http://xbrl.sec.gov/invest/2011/invest-2011-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/naics/2011-01-31" schemaLocation="http://xbrl.sec.gov/naics/2011/naics-2011-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/sic/2011-01-31" schemaLocation="http://xbrl.sec.gov/sic/2011/sic-2011-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/stpr/2011-01-31" schemaLocation="http://xbrl.sec.gov/stpr/2011/stpr-2011-01-31.xsd" />
  <xsd:annotation>
    <xsd:appinfo>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="ftnt-20110930_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="ftnt-20110930_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="ftnt-20110930_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="ftnt-20110930_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple" />
      <link:roleType id="Acquisitions" roleURI="http://www.fortinet.com/role/Acquisitions">
        <link:definition>2139100 - Disclosure - Acquisitions</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsAndContingencies" roleURI="http://www.fortinet.com/role/CommitmentsAndContingencies">
        <link:definition>2119100 - Disclosure - Commitments and Contingencies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedBalanceSheets" roleURI="http://www.fortinet.com/role/CondensedConsolidatedBalanceSheets">
        <link:definition>1001000 - Statement - Condensed Consolidated Balance Sheets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedBalanceSheetsParenthetical" roleURI="http://www.fortinet.com/role/CondensedConsolidatedBalanceSheetsParenthetical">
        <link:definition>1001500 - Statement - Condensed Consolidated Balance Sheets Parenthetical</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsOfCashFlows" roleURI="http://www.fortinet.com/role/CondensedConsolidatedStatementsOfCashFlows">
        <link:definition>1003000 - Statement - Condensed Consolidated Statements of Cash Flows</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsOfOperations" roleURI="http://www.fortinet.com/role/CondensedConsolidatedStatementsOfOperations">
        <link:definition>1002000 - Statement - Condensed Consolidated Statements of Operations</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsOfOperationsParentheticalParentheticals" roleURI="http://www.fortinet.com/role/CondensedConsolidatedStatementsOfOperationsParentheticalParentheticals">
        <link:definition>1002500 - Statement - Condensed Consolidated Statements of Operations Parenthetical (Parentheticals)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DeferredRevenue" roleURI="http://www.fortinet.com/role/DeferredRevenue">
        <link:definition>2116100 - Disclosure - Deferred Revenue</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DocumentAndEntityInformation" roleURI="http://www.fortinet.com/role/DocumentAndEntityInformation">
        <link:definition>0001000 - Document - Document and Entity Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EmployeeBenefitPlan" roleURI="http://www.fortinet.com/role/EmployeeBenefitPlan">
        <link:definition>2131100 - Disclosure - Employee Benefit Plan</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomePerShare" roleURI="http://www.fortinet.com/role/IncomePerShare">
        <link:definition>2113100 - Disclosure - Income Per Share</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxes" roleURI="http://www.fortinet.com/role/IncomeTaxes">
        <link:definition>2128100 - Disclosure - Income Taxes</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Inventorynet" roleURI="http://www.fortinet.com/role/Inventorynet">
        <link:definition>2107100 - Disclosure - Inventory&#8212;Net</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="InvestmentsAndFairValueMeasurements" roleURI="http://www.fortinet.com/role/InvestmentsAndFairValueMeasurements">
        <link:definition>2104100 - Disclosure - Investments and Fair Value Measurements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="PropertyAndEquipmentNet" roleURI="http://www.fortinet.com/role/PropertyAndEquipmentNet">
        <link:definition>2110100 - Disclosure - Property and Equipment - Net</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentInformation" roleURI="http://www.fortinet.com/role/SegmentInformation">
        <link:definition>2137100 - Disclosure - Segment Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquity" roleURI="http://www.fortinet.com/role/StockholdersEquity">
        <link:definition>2122100 - Disclosure - Stockholder's Equity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SummaryOfSignificantAccountingPolicies" roleURI="http://www.fortinet.com/role/SummaryOfSignificantAccountingPolicies">
        <link:definition>2101100 - Disclosure - Summary of Significant Accounting Policies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xsd:appinfo>
  </xsd:annotation>
  <xsd:element abstract="true" id="ftnt_AcquisitionsAbstract" name="AcquisitionsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_BalanceSheetParentheticalsAbstract" name="BalanceSheetParentheticalsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_CommitmentsAndContingenciesAbstract" name="CommitmentsAndContingenciesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_CondensedConsolidatedBalanceSheetsAbstract" name="CondensedConsolidatedBalanceSheetsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_CondensedConsolidatedStatementsOfCashFlowsAbstract" name="CondensedConsolidatedStatementsOfCashFlowsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_CondensedConsolidatedStatementsOfOperationsAbstract" name="CondensedConsolidatedStatementsOfOperationsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_CondensedConsolidatedStatementsOfOperationsParentheticalAbstract" name="CondensedConsolidatedStatementsOfOperationsParentheticalAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ftnt_CostOfRatableProductAndServices" name="CostOfRatableProductAndServices" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_DeferredRevenuesAbstract" name="DeferredRevenuesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_DeiAbstract" name="DeiAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_EmployeeBenefitPlanAbstract" name="EmployeeBenefitPlanAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_IncomeLossPerShareAbstract" name="IncomeLossPerShareAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_IncomeTaxesAbstract" name="IncomeTaxesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_InventoryAbstract" name="InventoryAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_InvestmentsAndFairValueMeasurementsAbstract" name="InvestmentsAndFairValueMeasurementsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ftnt_ProductGrossProfit" name="ProductGrossProfit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_PropertyAndEquipmentNetAbstract" name="PropertyAndEquipmentNetAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ftnt_RatableProductAndServicesGrossProfit" name="RatableProductAndServicesGrossProfit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="ftnt_RatableProductAndServicesRevenueNet" name="RatableProductAndServicesRevenueNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_SegmentInformationAbstract" name="SegmentInformationAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ftnt_ServicesGrossProfit" name="ServicesGrossProfit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ftnt_SummaryOfSignificantAccountingPoliciesAbstract" name="SummaryOfSignificantAccountingPoliciesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
</xsd:schema>
</XBRL>
