<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:01a0ea1c-67da-75ff-8294-e0b185ad0315,g:d3aed475-2e86-498b-bf32-ca2a35e28748-->
<link:linkbase 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" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:roleRef roleURI="http://www.fortinet.com/role/DocumentAndEntityInformation" xlink:type="simple" xlink:href="ftnt-20261028.xsd#DocumentAndEntityInformation"/>
  <link:presentationLink xlink:role="http://www.fortinet.com/role/DocumentAndEntityInformation" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CoverAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_01a0ea1c-67da-7799-9112-066b90dbe5d0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_DocumentType_01a0ea1c-67da-7799-9112-066b90dbe5d0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_01a0ea1c-67da-7485-a3d6-13fa155fe6d0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_DocumentPeriodEndDate_01a0ea1c-67da-7485-a3d6-13fa155fe6d0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_01a0ea1c-67da-77a3-b677-c5160cfbd6a6" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_EntityRegistrantName_01a0ea1c-67da-77a3-b677-c5160cfbd6a6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_01a0ea1c-67da-7b6a-a6bd-302ff6f6405c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_EntityIncorporationStateCountryCode_01a0ea1c-67da-7b6a-a6bd-302ff6f6405c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_01a0ea1c-67da-72ea-9347-a221a0c57021" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_EntityFileNumber_01a0ea1c-67da-72ea-9347-a221a0c57021" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_01a0ea1c-67da-79bb-8575-f96e765fea21" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_EntityTaxIdentificationNumber_01a0ea1c-67da-79bb-8575-f96e765fea21" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_01a0ea1c-67da-7709-aced-980073f3db28" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_EntityAddressAddressLine1_01a0ea1c-67da-7709-aced-980073f3db28" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_01a0ea1c-67da-7dfe-b9bc-cf5a1abc80db" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_EntityAddressCityOrTown_01a0ea1c-67da-7dfe-b9bc-cf5a1abc80db" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_01a0ea1c-67da-752b-8824-b9f44ad77a24" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_EntityAddressStateOrProvince_01a0ea1c-67da-752b-8824-b9f44ad77a24" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_01a0ea1c-67da-7ca3-a7b8-d629454671c1" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_EntityAddressPostalZipCode_01a0ea1c-67da-7ca3-a7b8-d629454671c1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_01a0ea1c-67da-7365-940a-3213fced1778" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:presentationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_CityAreaCode_01a0ea1c-67da-7365-940a-3213fced1778" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_01a0ea1c-67da-736b-b14b-530efc10365f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:presentationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_LocalPhoneNumber_01a0ea1c-67da-736b-b14b-530efc10365f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_01a0ea1c-67da-7e82-a054-8157e3b8e803" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_WrittenCommunications"/>
    <link:presentationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_WrittenCommunications_01a0ea1c-67da-7e82-a054-8157e3b8e803" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_01a0ea1c-67da-7f89-92f7-39dde2bd1e23" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SolicitingMaterial"/>
    <link:presentationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_SolicitingMaterial_01a0ea1c-67da-7f89-92f7-39dde2bd1e23" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_01a0ea1c-67da-7072-bdbc-352facfbaf3f" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementTenderOffer"/>
    <link:presentationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_PreCommencementTenderOffer_01a0ea1c-67da-7072-bdbc-352facfbaf3f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_01a0ea1c-67da-70c4-a1e2-e58a403c6554" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:presentationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_01a0ea1c-67da-70c4-a1e2-e58a403c6554" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_01a0ea1c-67da-747d-bcfd-bddaffca23e9" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:presentationArc order="17" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_Security12bTitle_01a0ea1c-67da-747d-bcfd-bddaffca23e9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_01a0ea1c-67da-7856-a73a-dc42294fd154" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:presentationArc order="18" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_TradingSymbol_01a0ea1c-67da-7856-a73a-dc42294fd154" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_01a0ea1c-67da-7639-8f1c-e1a1309892a7" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:presentationArc order="19" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_SecurityExchangeName_01a0ea1c-67da-7639-8f1c-e1a1309892a7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_01a0ea1c-67da-7bc7-a79e-5a194ebd2f44" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:presentationArc order="20" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_EntityEmergingGrowthCompany_01a0ea1c-67da-7bc7-a79e-5a194ebd2f44" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_01a0ea1c-67da-750e-864b-4b0ef34886f9" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:presentationArc order="21" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_EntityCentralIndexKey_01a0ea1c-67da-750e-864b-4b0ef34886f9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_01a0ea1c-67da-7652-a52b-bb71e593f2db" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:presentationArc order="22" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_01a0ea1c-67da-72bc-ad58-010ab1a4cda2" xlink:to="loc_dei_AmendmentFlag_01a0ea1c-67da-7652-a52b-bb71e593f2db" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
</link:linkbase>
