<SUBMISSION>
<ACCESSION-NUMBER>0001179110-15-003859
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20150226
<FILING-DATE>20150302
<DATE-OF-FILING-DATE-CHANGE>20150302
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>BOINGO WIRELESS INC
<CIK>0001169988
<ASSIGNED-SIC>4899
<IRS-NUMBER>000000000
<STATE-OF-INCORPORATION>DE
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>10960 WILSHIRE BLVD., SUITE 800
<CITY>LOS ANGELES
<STATE>CA
<ZIP>90024
<PHONE>310-586-5180
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>10960 WILSHIRE BLVD., SUITE 800
<CITY>LOS ANGELES
<STATE>CA
<ZIP>90024
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>Callahan Dawn
<CIK>0001570670
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-35155
<FILM-NUMBER>15666724
</FILING-VALUES>
<MAIL-ADDRESS>
<STREET1>C/O BOINGO WIRELESS, INC.
<STREET2>10960 WILSHIRE BLVD.SUITE 800
<CITY>LOS ANGELES
<STATE>CA
<ZIP>90024
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-02-26</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001169988</issuerCik>
        <issuerName>BOINGO WIRELESS INC</issuerName>
        <issuerTradingSymbol>WIFI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001570670</rptOwnerCik>
            <rptOwnerName>Callahan Dawn</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>10960 WILSHIRE BLVD.</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 800</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90024</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Marketing Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2015-02-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>43369</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>43369</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>43369</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Performance Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2015-02-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>13683</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>13683</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13683</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit represents a contingent right to receive one share of Boingo Wireless, Inc. common stock.</footnote>
        <footnote id="F2">The restricted stock units will vest in twelve successive equal quarterly installments beginning on March 1, 2015, so that the restricted stock units will become fully vested on March 1, 2018.  The restricted stock units will be settled in shares of common stock that will be delivered to the Reporting Person shortly after each vesting date.</footnote>
        <footnote id="F3">This transaction reflects, with respect to the number of shares reported, achievement of the fiscal year 2014 performance goals applicable to the Reporting Person's fiscal year 2014 performance restricted stock unit award. Of these performance restricted stock units, 1/3 will vest on March 1, 2015 and the balance will vest in a series of eight successive equal quarterly installments thereafter, so that the performance restricted stock units will become fully vested on March 1, 2017. The performance restricted stock units will be settled in shares of common stock that will be delivered to the Reporting Person shortly after each vesting date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Efren Medina as Attorney-in-Fact for Dawn Callahan</signatureName>
        <signatureDate>2015-03-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
