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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2014-06-27</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001344413</issuerCik>
        <issuerName>Alexza Pharmaceuticals Inc.</issuerName>
        <issuerTradingSymbol>ALXA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001612008</rptOwnerCik>
            <rptOwnerName>Kamemoto Edwin S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ALEXZA PHARMACEUTICALS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>2091 STIERLIN COURT</rptOwnerStreet2>
            <rptOwnerCity>MOUNTAIN VIEW</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94043</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP, Regulatory Affairs</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24737</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>12.30</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2021-02-21</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2071</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>15.30</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2021-07-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9999</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>3.47</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2013-07-26</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2022-07-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>15000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>3.47</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2013-07-26</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2022-07-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.42</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2014-03-29</value>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2024-05-20</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>43750</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.57</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2015-06-27</value>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2024-06-26</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>24000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Includes 21,875 shares issued as restricted stock units (&quot;RSUs&quot;) under the Issuer's 2005 Equity Incentive Plan (the &quot;Plan&quot;).  If the Issuer's common stock listed on the Nasdaq Global Market has traded at or above $8.63 on each trading day of any 30-day trading period after March 29, 2013 (the &quot;Price Trigger&quot;), then 50% of the RSUs will vest on the later of March 29, 2016 and the date on which the Price Trigger is met, and the remaining 50% of the RSUs will vest on the later of March 29, 2017 and the date on which the Price Trigger is met, provided in each case that the Reporting Person remains employed by the Company through the applicable vesting date.</footnote>
        <footnote id="F2">Fully vested.</footnote>
        <footnote id="F3">Grant to the Reporting Person of a stock option under the Plan. 25% of the shares vest on the first annual anniversary of the vesting commencement date, and the remaining 75% in monthly installments of 2.0833% thereafter for 36 months until fully vested, provided (i) that if application of the vesting percentage at a given anniversary results in a fractional share, such fractional share will be rounded downward to the nearest whole share, with any rounding balance carried forward and applied to the number of shares for which such option will be exercisable, if at all, at the 48th monthly anniversary of the vesting commencement date; and (ii) that in each case at the relevant annual or monthly anniversary such optionee's employment has not been Terminated as defined in and as determined under the Plan. The option expires ten years after the date of grant.</footnote>
        <footnote id="F4">Grant to the Reporting Person of a stock option under the Plan.  50% of the shares vested March 29, 2014.  The remaining shares vest in equal monthly installments thereafter for 12 months until fully vested, provided in each case that the relevant monthly anniversary such optionee's employment has not been Terminated as defined in and as determined under the Plan.  The option expires ten years after the date of grant.</footnote>
        <footnote id="F5">Grant to the Reporting Person of a stock option under the Plan.  25% vesting on the one year anniversary of the vesting commencement date and the remaining 75% vesting in equal monthly installments thereafter over 36 months, provided that if application of the vesting percentage at a given anniversary results in a fractional share, such fractional share will be rounded downward to the nearest whole share, with any rounding balance carried forward and applied to the number of shares for which such option will be exercisable, if at all, at the 36th monthly anniversary of the vesting commencement date, provided further that at the relevant vesting dates such optionee's consulting relationship has not been Terminated as defined in and as determined under the Plan.  The option expires ten years after the date of grant.</footnote>
    </footnotes>

    <remarks>Attachment: Exhibit 24 - Power of Attorney</remarks>

    <ownerSignature>
        <signatureName>/s/ Edwin S. Kamemoto</signatureName>
        <signatureDate>2014-06-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
