<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0305</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-06-07</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001175454</issuerCik>
        <issuerName>FLEETCOR TECHNOLOGIES INC</issuerName>
        <issuerTradingSymbol>FLT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001131656</rptOwnerCik>
            <rptOwnerName>SUMMIT VENTURES VI-A LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET</rptOwnerStreet1>
            <rptOwnerStreet2>18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001131666</rptOwnerCik>
            <rptOwnerName>SUMMIT VENTURES VI-B LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET</rptOwnerStreet1>
            <rptOwnerStreet2>18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001131279</rptOwnerCik>
            <rptOwnerName>SUMMIT VI ADVISORS FUND LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SUMMIT PARTNERS</rptOwnerStreet1>
            <rptOwnerStreet2>222 BERKELEY STREET, 18TH FLORR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001131280</rptOwnerCik>
            <rptOwnerName>SUMMIT VI ENTREPRENEURS FUND LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SUMMIT PARTNERS</rptOwnerStreet1>
            <rptOwnerStreet2>222 BERKELEY STREET, 18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001258822</rptOwnerCik>
            <rptOwnerName>SUMMIT INVESTORS VI LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SUMMIT PARTNERS</rptOwnerStreet1>
            <rptOwnerStreet2>222 BERKELEY STREET, 18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001435565</rptOwnerCik>
            <rptOwnerName>Summit Investors I, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET, 18TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001494616</rptOwnerCik>
            <rptOwnerName>Summit Investors I (UK), L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET, 18TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001030825</rptOwnerCik>
            <rptOwnerName>SUMMIT SUBORDINATED DEBT FUND II L P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SUMMIT PARTNERS</rptOwnerStreet1>
            <rptOwnerStreet2>222 BERKELEY STREET, 18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001486421</rptOwnerCik>
            <rptOwnerName>Summit Partners Private Equity Fund VII-A, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET</rptOwnerStreet1>
            <rptOwnerStreet2>18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001385242</rptOwnerCik>
            <rptOwnerName>Summit Partners Private Equity Fund VII B L P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET</rptOwnerStreet1>
            <rptOwnerStreet2>18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2012-06-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4000000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>36.95</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15040170</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares sold by the following entities: 2,272,956 shares of common stock sold by Summit Ventures VI-A, L.P., 947,914 shares of common stock sold by Summit Ventures VI-B, L.P., 47,271 shares of common stock sold by Summit VI Advisors Fund, L.P., 72,577 shares of common stock sold by Summit VI Entrepreneurs Fund, L.P., 19,032 shares of common stock sold by Summit Investors VI, L.P., 58,850 shares of common stock sold by Summit Subordinated Debt Fund II, L.P., 361,798 shares of common stock sold by Summit Partners Private Equity Fund VII-A, L.P., 217,302 shares of common stock sold by Summit Partners Private Equity Fund VII-B, L.P., 2,082 shares of common stock sold by Summit Investors I, LLC and 218 shares of common stock sold by Summit Investors I (UK), L.P.</footnote>
        <footnote id="F2">Represents shares held by the following entities: 8,546,411 shares of common stock held by Summit Ventures VI-A, L.P., 3,564,195 shares of common stock held by Summit Ventures VI-B, L.P., 177,742 shares of common stock held by Summit VI Advisors Fund, L.P., 272,893 shares of common stock held by Summit VI Entrepreneurs Fund, L.P., 71,560 shares of common stock held by Summit Investors VI, L.P., 221,280 shares of common stock held by Summit Subordinated Debt Fund II, L.P., 1,360,378 shares of common stock held by Summit Partners Private Equity Fund VII-A, L.P., 817,063 shares of common stock held by Summit Partners Private Equity Fund VII-B, L.P., 7,827 shares of common stock held by Summit Investors I, LLC and 821 shares of common stock held by Summit Investors I (UK), L.P.</footnote>
    </footnotes>

    <remarks>The entities mentioned in Footnote 1 and 2 are collectively referred to as the &quot;Summit Entities.&quot; Each of the Summit Entities disclaims beneficial ownership of all shares except those specifically listed in the Footnotes as held by such entity, except to the extent of each such entity's pecuniary interest therein.</remarks>

    <ownerSignature>
        <signatureName>Summit Ventures VI-A, L.P., by Summit Partners VI (GP), L.P., its GP, by Summit Partners VI (GP), LLC, its GP, by Summit Partners, L.P., its Manager, by Summit Master Company, LLC, its GP, by Robin W. Devereux, POA for Joseph F. Trustey, Member</signatureName>
        <signatureDate>2012-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit Ventures VI-B, L.P., by Summit Partners VI (GP), L.P., Its GP, by Summit Partners VI (GP), LLC, Its GP, by Summit Partners, L.P., its Manager, by Summit Master Company, LLC, its GP, by Robin W. Devereux, POA for Joseph F. Trustey,  Member</signatureName>
        <signatureDate>2012-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit VI Advisors Fund, L.P., by Summit Partners VI (GP), L.P., its GP, by Summit Partners VI (GP), LLC, its GP, by Summit Partners, L.P., its Manager, by Summit Master Company, LLC, its GP, by Robin W. Devereux, POA for Joseph F. Trustey, Member</signatureName>
        <signatureDate>2012-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit VI Entrepreneurs Fund, L.P., by Summit Partners VI (GP), L.P., its GP, by Summit Partners VI (GP), LLC, its GP, by Summit Partners, L.P., its Manager, by Summit Master Company, LLC, its GP, by Robin W. Devereux, POA for Joseph F. Trustey, Member</signatureName>
        <signatureDate>2012-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit Investors VI, L.P., by Summit Partners VI (GP), L.P., its GP, by Summit Partners VI (GP), LLC, its GP, by Summit Partners, L.P., its Manager, by Summit Master Company, LLC, its GP, by Robin W. Devereux, POA for Joseph F. Trustey, Member</signatureName>
        <signatureDate>2012-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit Investors I, LLC, by Summit Investors Management, LLC, its Manager, by Summit Partners, L.P., its Managing Member, by Summit Master Company, LLC, its general partner, by Robin W. Devereux, POA for Joseph F. Trustey, Member</signatureName>
        <signatureDate>2012-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit Investors I (UK), L.P., by Summit Investors Management, LLC, its General Partner, by Summit Partners, L.P., its Managing Member, by Summit Master Company, its General Partner, by Robin W. Devereux, POA for Joseph F. Trustey, Member</signatureName>
        <signatureDate>2012-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit Partners Subordinated Debt Fund II,  L.P., by Summit Partners Subordinated Debt II, LLC, its GP, by Stamps, Woodsum &amp; Company IV, its GP, by Summit Partners, L.P., its GP, by Summit Master Company, LLC, its GP, by Robin W. Devereux, POA for Joseph</signatureName>
        <signatureDate>2012-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit Partners Private Equity Fund VII-A, L.P., by Summit Partners PE VII, L.P., its GP, by Summit Partners PE VII, LLC, its GP, by Summit Partners, L.P., its GP, by Summit Master Company, LLC, its GP, by Robin W. Devereux, POA for Joseph Trustey, Member</signatureName>
        <signatureDate>2012-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit Partners Private Equity Fund VII-B, L.P., by Summit Partners PE VII, L.P., its GP, by Summit Partners PE VII, LLC, its GP, by Summit Partners, L.P., its GP, by Summit Master Company, LLC, its GP, by Robin W. Devereux, POA for Joseph Trustey, Member</signatureName>
        <signatureDate>2012-06-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
