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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-06-15</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001131554</issuerCik>
        <issuerName>SYNCHRONOSS TECHNOLOGIES INC</issuerName>
        <issuerTradingSymbol>SNCR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001355152</rptOwnerCik>
            <rptOwnerName>Rosewood Capital Associates IV LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE MARITIME PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1401</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of Group 10% Owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001355153</rptOwnerCik>
            <rptOwnerName>Rosewood Capital IV LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE MARITIME PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1401</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of Group 10% Owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001366160</rptOwnerCik>
            <rptOwnerName>Rosewood Capital Associates LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE MARITIME PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1401</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of Group 10% owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001366161</rptOwnerCik>
            <rptOwnerName>Rosewood Capital IV Associates LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE MARITIME PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1401</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of Group 10% Owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001043950</rptOwnerCik>
            <rptOwnerName>ROSEWOOD CAPITAL III LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE MARITIME PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1401</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of Group 10% owner</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001228858</rptOwnerCik>
            <rptOwnerName>ANDERSON KYLE A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE MARITIME PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1401</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Managing Member</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001344609</rptOwnerCik>
            <rptOwnerName>Adams Byron K JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE MARITIME PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1401</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Managing Member</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-06-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>257960</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2321538</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Reflects 42,097 shares sold by Rosewood Capital III, L.P., 213,829 shares sold by Rosewood Capital IV, L.P. and 2,034 shares sold by Rosewood Capital IV Associates, L.P.  Rosewood Capital Associates, LLC is the general partner of Rosewood Capital III, L.P. and Rosewood Capital Associates IV, LLC is the general partner of Rosewood Capital IV, L.P. and Rosewood Capital IV Associates, L.P.  Byron K. Adams Jr. and Kyle A. Anderson are the managing members of Rosewood Capital Associates, LLC.  Each of Byron K. Adams Jr., Kyle A. Anderson and Peter Breck are the managing members of Rosewood Capital Associates IV, LLC, and each of them disclaims beneficial ownership of the shares held by Rosewood Capital IV, L.P. and Rosewood Capital IV Associates, L.P. except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Kyle A. Anderson, Managing Member</signatureName>
        <signatureDate>2006-06-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Byron K. Adams Jr.</signatureName>
        <signatureDate>2006-06-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Kyle A. Anderson</signatureName>
        <signatureDate>2006-06-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Kyle A. Anderson, Managing Member</signatureName>
        <signatureDate>2006-06-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Kyle A. Anderson, Managing Member</signatureName>
        <signatureDate>2006-06-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Kyle A. Anderson, Managing Member</signatureName>
        <signatureDate>2006-06-15</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Kyle A. Anderson, Managing Member</signatureName>
        <signatureDate>2006-06-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
