<SUBMISSION>
<ACCESSION-NUMBER>0001179110-16-018413
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20160201
<FILING-DATE>20160203
<DATE-OF-FILING-DATE-CHANGE>20160203
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>BOINGO WIRELESS INC
<CIK>0001169988
<ASSIGNED-SIC>4899
<IRS-NUMBER>000000000
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>10960 WILSHIRE BLVD., 23RD FLOOR
<CITY>LOS ANGELES
<STATE>CA
<ZIP>90024
<PHONE>310-586-5180
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>10960 WILSHIRE BLVD., 23RD FLOOR
<CITY>LOS ANGELES
<STATE>CA
<ZIP>90024
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>Peterson Derek
<CIK>0001570558
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-35155
<FILM-NUMBER>161385509
</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>2016-02-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001570558</rptOwnerCik>
            <rptOwnerName>Peterson Derek</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>10960 WILSHIRE BLVD.</rptOwnerStreet1>
            <rptOwnerStreet2>23RD FLOOR</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 Technology Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2016-02-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>33344</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>33344</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>33344</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 over continuous service beginning on February 1, 2016, so that the restricted stock units will become fully vested on February 1, 2019. 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>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Efren Medina as Attorney-in-Fact for Derek Peterson</signatureName>
        <signatureDate>2016-02-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
