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

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2006-10-17</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000799729</issuerCik>
        <issuerName>PAREXEL INTERNATIONAL CORP</issuerName>
        <issuerTradingSymbol>PRXL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001266051</rptOwnerCik>
            <rptOwnerName>LINDOP CHRISTOPHER J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>INVERNESS MEDICAL INNOVATIONS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>51 SAWYER ROAD</rptOwnerStreet2>
            <rptOwnerCity>WALTHAM</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02453</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>W. Brett Davis, Attorney-in-Fact</signatureName>
        <signatureDate>2006-10-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
