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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-04-16</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001161175</rptOwnerCik>
            <rptOwnerName>KLEINHEINZ CAPITAL PARTNERS, INC.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>301 COMMERCE STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1900</rptOwnerStreet2>
            <rptOwnerCity>FORT WORTH</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>76102</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Terminating a 13(d) 10% Group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001421810</rptOwnerCik>
            <rptOwnerName>Kleinheinz Capital Partners LDC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O WALKERS SPV LTD.</rptOwnerStreet1>
            <rptOwnerStreet2>WALKER HOUSE, 87 MARY STREET</rptOwnerStreet2>
            <rptOwnerCity>GEORGE TOWN</rptOwnerCity>
            <rptOwnerState>E9</rptOwnerState>
            <rptOwnerZipCode>KY1-9001</rptOwnerZipCode>
            <rptOwnerStateDescription>CAYMAN ISLANDS</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of a 10% Group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001165595</rptOwnerCik>
            <rptOwnerName>GLOBAL UNDERVALUED SECURITIES MASTER FUND LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O BNY MELLON ALTERNATIVE INVESTMENT SE</rptOwnerStreet1>
            <rptOwnerStreet2>48 PAR LA VILLE ROAD SUITE 464</rptOwnerStreet2>
            <rptOwnerCity>HAMILTON HMII</rptOwnerCity>
            <rptOwnerState>D0</rptOwnerState>
            <rptOwnerZipCode>0000</rptOwnerZipCode>
            <rptOwnerStateDescription>BERMUDA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of a 10% Group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001306112</rptOwnerCik>
            <rptOwnerName>Global Undervalued Securities Fund Ltd</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O BNY MELLON ALTERNATIVE INVESTMENT SE</rptOwnerStreet1>
            <rptOwnerStreet2>48 PAR LA VILLE ROAD SUITE 464</rptOwnerStreet2>
            <rptOwnerCity>HAMILTON HM 11 BERMUDA</rptOwnerCity>
            <rptOwnerState>D0</rptOwnerState>
            <rptOwnerZipCode>00000</rptOwnerZipCode>
            <rptOwnerStateDescription>BERMUDA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of a 10% Group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001081865</rptOwnerCik>
            <rptOwnerName>KLEINHEINZ JOHN B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>301 COMMERCE STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1900</rptOwnerStreet2>
            <rptOwnerCity>FORT WORTH</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>76102</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of a 10% Group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001090351</rptOwnerCik>
            <rptOwnerName>GLOBAL UNDERVALUED SECURITIES FUND LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O BNY MELLON ALTERNATIVE INVESTMENT SE</rptOwnerStreet1>
            <rptOwnerStreet2>48 PAR LA VILLE ROAD SUITE 464</rptOwnerStreet2>
            <rptOwnerCity>HAMILTON</rptOwnerCity>
            <rptOwnerState>D0</rptOwnerState>
            <rptOwnerZipCode>HM11</rptOwnerZipCode>
            <rptOwnerStateDescription>BERMUDA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of a 10% Group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001302660</rptOwnerCik>
            <rptOwnerName>Global Undervalued Securities Fund QP L P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O BNY MELLON ALTERNATIVE INVESTMENT SE</rptOwnerStreet1>
            <rptOwnerStreet2>48 PAR LA VILLE ROAD SUITE 464</rptOwnerStreet2>
            <rptOwnerCity>HAMILTON N H 11</rptOwnerCity>
            <rptOwnerState>D0</rptOwnerState>
            <rptOwnerZipCode>00000</rptOwnerZipCode>
            <rptOwnerStateDescription>BERMUDA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of a 10% Group</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>402061</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"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares of common stock (&quot;Common Stock&quot;) of Alloy, Inc. (the &quot;Issuer&quot;) directly beneficially owned by Global Undervalued Securities Master Fund, L.P. (&quot;Global Master&quot;).</footnote>
        <footnote id="F2">Pursuant to a Group Termination Agreement dated April 16, 2010, Kleinheinz Capital Partners, Inc. (&quot;Kleinheinz&quot;), Kleinheinz Capital Partners LDC (&quot;LDC&quot;), Global Undervalued
Securities Fund, L.P. (&quot;Global, L.P.&quot;), Global Undervalued Securities Fund (QP), L.P. (&quot;Global QP&quot;), Global Undervalued Securities Fund, Ltd. (&quot;Global Ltd.&quot;), Global Master and John B. Kleinheinz (&quot;Mr. Kleinheinz&quot;, and collectively with Kleinheinz, LDC, Global, L.P., Global QP, Global Ltd. and Global Master, the &quot;Reporting Persons&quot;) terminated their &quot;group&quot; for
purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended (the &quot;Exchange Act&quot;) with (see Footnote 3)</footnote>
        <footnote id="F3">(cont. Footnote 2) BD Media Investors LP, SRB Greenway Opportunity Fund, (QP), L.P., SRB Greenway Opportunity Fund, L.P., SRB Management, L.P., BC Advisors, LLC, Steven R.
Becker and Matthew A. Drapkin (the &quot;Greenway Parties&quot;) and terminated the Joint Filing Agreement entered into on December 17, 2009 by and between the Reporting Persons and the
Greenway Parties. After giving effect to such termination, the Reporting Persons are no longer subject to Section 16 of the Exchange Act.</footnote>
        <footnote id="F4">Kleinheinz, as the investment manager of Global, L.P., Global QP, Global Ltd. and Global Master; LDC, as the general partner of Global, L.P. and Global QP; Global, L.P., as a general
partner of Global Master; Global QP, as a general partner of Global Master; Global Ltd., as a general partner of Global Master; and Mr. Kleinheinz as the sole director and President of
Kleinheinz and a director of LDC, 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. Kleinheinz,
LDC, Global, L.P., Global QP, Global Ltd. and Mr. Kleinheinz disclaim any beneficial ownership of any Common Stock listed herein, except to the extent of any pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>See Exhibit 99.1</signatureName>
        <signatureDate>2010-04-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
