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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-01-25</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001080359</issuerCik>
        <issuerName>ALLOY INC</issuerName>
        <issuerTradingSymbol>ALOY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001477651</rptOwnerCik>
            <rptOwnerName>BD MEDIA INVESTORS LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>300 CRESCENT COURT</rptOwnerStreet1>
            <rptOwnerStreet2>STE 1111</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of a 13(d) 10% Group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001451722</rptOwnerCik>
            <rptOwnerName>SRB GREENWAY OPPORTUNITY FUND (QP) LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SRB MANAGEMENT LP</rptOwnerStreet1>
            <rptOwnerStreet2>300 CRESCENT COURT, SUITE 1111</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of 10% 13(d) group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001451721</rptOwnerCik>
            <rptOwnerName>SRB GREENWAY OPPORTUNITY FUND LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>300 CRESCENT COURT</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1111</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of 10% 13(d) group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001346543</rptOwnerCik>
            <rptOwnerName>SRB Management, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>300 CRESCENT COURT</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1111</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of 10% 13(d) group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001349003</rptOwnerCik>
            <rptOwnerName>BC Advisors LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>300 CRESCENT COURT</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1111</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of 10% 13(d) group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001349005</rptOwnerCik>
            <rptOwnerName>Becker Steven R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>300 CRESCENT COURT</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1111</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of 10% 13(d) group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001458693</rptOwnerCik>
            <rptOwnerName>Drapkin Matthew A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>300 CRESCENT COURT</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1111</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of 10% 13(d) group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-01-25</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>15000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.85</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>645137</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents 645,137 shares of common stock (&quot;Common Stock&quot;) of Alloy, Inc. (the &quot;Issuer&quot;) directly beneficially owned by BD Media Investors LP (&quot;BD Media&quot;).</footnote>
        <footnote id="F2">On December 17, 2009, BD Media, SRB Greenway Opportunity Fund (QP), L.P. (&quot;Greenway Opportunity QP&quot;), SRB Greenway Opportunity Fund, L.P. (&quot;Greenway Opportunity, L.P.&quot;), SRB Management, L.P. (&quot;SRB Management&quot;), BC Advisors, LLC (&quot;BCA&quot;), Steven R. Becker (&quot;Mr. Becker&quot;) and Matthew A. Drapkin (&quot;Mr. Drapkin&quot;, and collectively with BD Media, Greenway Opportunity QP, Greenway Opportunity, L.P., SRB Management, BCA and Mr. Becker, the &quot;Reporting Persons&quot;) and Kleinheinz Capital Partners, Inc., Kleinheinz Capital Partners LDC, Global Undervalued Securities Master Fund, L.P., Global Undervalued Securities Fund, L.P., Global Undervalued Securities Fund (QP), L.P., Global Undervalued Securities Fund, Ltd., and John B. Kleinheinz (the &quot;Kleinheinz Parties&quot;) entered into a Joint Filing Agreement (the &quot;Joint Filing Agreement&quot;).  (Continued in Footnote 3.)</footnote>
        <footnote id="F3">Pursuant to the Joint Filing Agreement, the Reporting Persons and the Kleinheinz Parties agreed to coordinate their actions with respect to the purchase and sale of Common Stock and discussions over certain matters with the Issuer.</footnote>
        <footnote id="F4">As a result of the agreements contained in the Joint Filing Agreement, the Reporting Persons may be deemed to be members of a &quot;group&quot; for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended (the &quot;Exchange Act&quot;) with the Kleinheinz Parties, and, therefore, may be deemed to beneficially own Common Stock beneficially owned by the Kleinheinz Parties.  The Reporting Persons disclaim beneficial ownership of and pecuniary interest in any shares of Common Stock beneficially owned by the Kleinheinz Parties, and this Form 4 and the filing hereof shall not be deemed an admission that any Reporting Person is a beneficial owner of any shares of Common Stock for any purpose, other than the Common Stock reported in Table 1 and as reported in Footnotes 5 and 6, or that any Reporting Person is a member of a &quot;group&quot;.  This Form 4 does not reflect any Common Stock owned, acquired or disposed of by the Kleinheinz Parties.</footnote>
        <footnote id="F5">Greenway Opportunity QP directly beneficially owns 264,369 shares of Common Stock.  Greenway Opportunity, L.P. directly beneficially owns 32,214 shares of Common Stock.  SRB Management, as the general partner of, and investment manager for, BD Media, Greenway Opportunity QP and Greenway Opportunity, L.P.; BCA, as the general partner of SRB Management; and Mr. Becker and Mr. Drapkin, as the sole members and co-managing members of BCA and limited partners of SRB Management, may in each case be deemed to be beneficial owners of the securities reported herein for purposes of Rule 16a-1(a) of the Exchange Act.  (Continued in Footnote 6.)</footnote>
        <footnote id="F6">SRB Management, BCA, Mr. Becker and Mr. Drapkin disclaim any beneficial ownership of any Common Stock listed herein, except to the extent of any pecuniary interest therein.  BD Media disclaims beneficial ownership of the Common Stock directly beneficially owned by Greenway Opportunity QP and Greenway Opportunity, L.P.; Greenway Opportunity QP disclaims beneficial ownership of the Common Stock directly beneficially owned by BD Media and Greenway Opportunity, L.P.; and Greenway Opportunity, L.P. disclaims beneficial ownership of the Common Stock directly beneficially owned by BD Media and Greenway Opportunity QP.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>see exhibit 99.1**</signatureName>
        <signatureDate>2010-01-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
