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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-01-24</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001374993</issuerCik>
        <issuerName>NextWave Wireless Inc.</issuerName>
        <issuerTradingSymbol>WAVE.PK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001118042</rptOwnerCik>
            <rptOwnerName>VOGEL CARL E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O NEXTWAVE WIRELESS INC.</rptOwnerStreet1>
            <rptOwnerStreet2>12264 EL CAMINO REAL, SUITE 305</rptOwnerStreet2>
            <rptOwnerCity>SAN DIEGO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92130</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Common Stock Options (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.17</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2013-01-24</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>200000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.83</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2022-02-16</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>200000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">NextWave Wireless Inc. (the &quot;Issuer&quot;) was acquired (the &quot;Merger&quot;) pursuant to that certain Agreement and Plan of Merger, dated as of August 1, 2012 (the &quot;Merger Agreement&quot;), by and among the Issuer, AT&amp;T Inc.  (&quot;Parent&quot;), and Rodeo Acquisition Sub Inc., a wholly owned subsidiary of Parent (&quot;Merger Sub&quot;). These options were cancelled in the Merger in exchange for a cash payment of  $166,000 in the aggregate, representing the product of (x) the excess if any, of (A) $1.00 over (B) the per share exercise price of such option ($0.17 per share) and (y) the number of shares of Common Stock for which such option has not been previously exercised.</footnote>
        <footnote id="F2">All other stock options held by the Reporting Person were cancelled as of the Effective Time for no value.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Carl E. Vogel</signatureName>
        <signatureDate>2013-01-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
