UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): April 19, 2012

Smith Micro Software, Inc.

(Exact name of registrant as specified in its charter)

51 Columbia

Aliso Viejo, California 92656

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: (949) 362-5800

None

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

The information set forth under “Item 3.03 Material Modification to Rights of Securities Holders” is incorporated herein by reference.

On April 19, 2012, the Board of Directors of Smith Micro Software, Inc. (the “Company”) declared a dividend of one preferred share purchase right (a “Right”) for each outstanding share of Common Stock, par value $0.001 per share (the “Common Shares”) outstanding on April 27, 2012 (the “Record Date”) to the stockholders of record on that date. Each Right entitles the registered holder to purchase from the Company one one-thousandths (1/1,000) of a share (each such one one-thousandth (1/1,000) of a share being a “Unit”) of Series A Junior Participating Preferred Stock, par value $0.001 per share (the “Preferred Stock”), of the Company, at a price of Ten Dollars ($10.00) per Unit of Preferred Stock (the “Purchase Price”), subject to adjustment. The description and terms of the Rights are set forth in a Stockholder Rights Agreement, dated April 24, 2012 (the “Rights Agreement”), between the Company and Computershare Trust Company, N.A., as Rights Agent (the “Rights Agent”).

Until the earlier to occur of (i) ten (10) days following a public announcement that a person or group of affiliated or associated persons, with certain exceptions (an “Acquiring Person”), has acquired beneficial ownership of 20% or more of the outstanding Common Shares or (ii) ten (10) Business Days (or such later date as may be determined by action of the Board of Directors prior to such time as any Person becomes an Acquiring Person) following the commencement of, or announcement of an intention to make, a tender offer or exchange offer the consummation of which would result in the beneficial ownership by a person or group of 20% or more of the outstanding Common Shares (the earlier of such dates being called the “Distribution Date”), the Rights will be evidenced, with respect to any of the Common Share certificates outstanding as of the Record Date, by such Common Share certificate with a copy of this Summary of Rights attached thereto.

The Stockholder Rights Agreement

The Rights Agreement provides that, until the Distribution Date, the Rights will be transferred with and only with the Common Shares. Until the Distribution Date (or earlier redemption or expiration of the Rights), new Common Share certificates issued after the Record Date or upon transfer or new issuance of Common Shares will contain a notation incorporating the Rights Agreement by reference. Until the Distribution Date (or earlier redemption or expiration of the Rights), the surrender for transfer of any certificates for Common Shares outstanding as of the Record Date, even without such notation or a copy of this Summary of Rights being attached thereto, will also constitute the transfer of the Rights associated with the Common Shares represented by such certificate. As soon as practicable following the Distribution Date, separate certificates evidencing the Rights (“Right Certificates”) will be mailed to holders of record of the Common Shares as of the Close of Business on the Distribution Date and such separate Right Certificates alone will evidence the Rights.

The Rights are not exercisable until the Distribution Date. The Rights will expire on April 17, 2015 (the “Final Expiration Date”), unless the Final Expiration Date is extended or unless the Rights are earlier redeemed or exchanged by the Company, in each case, as described below.

The Purchase Price payable, and the number of shares of Preferred Stock or other securities or property issuable, upon exercise of the Rights are subject to adjustment from time to time to prevent dilution (i) in the event of a stock dividend on, or a subdivision, combination or reclassification of, the Preferred Stock, (ii) upon the grant to holders of the Preferred Stock of certain rights or warrants to

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subscribe for or purchase Preferred Stock at a price, or securities convertible into Preferred Stock with a conversion price, less than the then current market price of the Preferred Stock or (iii) upon the distribution to holders of the Preferred Stock of evidences of indebtedness or assets (excluding regular periodic cash dividends paid out of earnings or retained earnings or dividends payable in Preferred Stock) or of subscription rights or warrants (other than those referred to above).

The number of outstanding Rights and the number of Units of Preferred Stock issuable upon exercise of each Right are also subject to adjustment in the event of a stock split of the Common Shares or a stock dividend on the Common Shares payable in Common Shares or subdivisions, consolidations or combinations of the Common Shares occurring, in any such case, prior to the Distribution Date.

Preferred Stock purchasable upon exercise of the Rights will not be redeemable. Each share of Preferred Stock will be entitled to a quarterly dividend payment of 1,000 times the dividend declared per Common Share. In the event of liquidation, the holders of the Preferred Stock will be entitled to an aggregate payment of 1,000 times the aggregate payment made per Common Share. Each share of Preferred Stock will have 1,000 votes, voting together with the Common Shares. In the event of any merger, consolidation or other transaction in which Common Shares are exchanged, each share of Preferred Stock will be entitled to receive 1,000 times the amount received per Common Share. These rights are protected by customary anti-dilution provisions.

Because of the nature of the Preferred Stock dividend, liquidation and voting rights, the value of the one Unit of Preferred Stock purchasable upon exercise of each Right should approximate the value of one Common Share.

Effects of the Rights

From and after the time any Person becomes an Acquiring Person, any Rights acquired or beneficially owned by an Acquiring Person or an Associate or Affiliate of an Acquiring Person (as such terms are defined in the Rights Agreement) on or after the earlier of (x) the date of such event and (y) the Distribution Date (as such term is defined in the Rights Agreement) shall become void, and any holder of such Rights shall thereafter have no right to exercise such Rights.

“Flip-In” Provisions. In the event that any person becomes an Acquiring Person, proper provision shall be made so that each holder of a Right, other than Rights beneficially owned by the Acquiring Person and its Affiliates and Associates (which will thereafter be void), will thereafter have the right to receive upon exercise that number of Common Shares having a market value of two times the exercise price of the Right. If the Company does not have sufficient Common Shares to satisfy such obligation to issue Common Shares, or if the Board of Directors so elects, the Company shall deliver upon payment of the exercise price of a Right an amount of cash or securities equivalent in value to the Common Shares issuable upon exercise of a Right; provided that, if the Company fails to meet such obligation within thirty (30) days following the date a Person becomes an Acquiring Person, the Company must deliver, upon exercise of a Right but without requiring payment of the exercise price then in effect, Common Shares (to the extent available) and cash equal in value to the difference between the value of the Common Shares otherwise issuable upon the exercise of a Right and the exercise price then in effect. The Board of Directors may extend the thirty (30) day period described above for up to an additional sixty (60) days to permit the taking of action that may be necessary to authorize sufficient additional Common Shares to permit the issuance of Common Shares upon the exercise in full of the Rights.

At any time after any Person becomes an Acquiring Person and prior to the acquisition by any person or group of a majority of the outstanding Common Shares, the Board of Directors of the Company may exchange the Rights (other than Rights owned by such person or group which have become void), in whole or in part, at an exchange ratio of one Common Share per Right (subject to adjustment).

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“Flip-Over” Provisions. In the event that, at any time after a Person becomes an Acquiring Person, the Company is acquired in a merger or other business combination transaction or 50% or more of its consolidated assets or earning power are sold, proper provision will be made so that each holder of a Right will thereafter have the right to receive, upon the exercise thereof at the then current exercise price of the Right, that number of shares of common stock of the acquiring company which at the time of such transaction will have a market value of two times the exercise price of the Right.

With certain exceptions, no adjustment in the Purchase Price will be required until cumulative adjustments require an adjustment of at least 1% in such Purchase Price. No fractional Preferred Stock will be issued (other than fractions which are integral multiples of Units of Preferred Stock, which may, at the election of the Company, be evidenced by depositary receipts) and in lieu thereof, an adjustment in cash will be made based on the market price of the Preferred Stock on the last Trading Day prior to the date of exercise.

At any time prior to the time any Person becomes an Acquiring Person, the Board of Directors of the Company may redeem the Rights in whole, but not in part, at a price of $0.001 per Right (the “Redemption Price”). The redemption of the Rights may be made effective at such time, on such basis and with such conditions as the Board of Directors in its sole discretion may establish. Immediately upon any redemption of the Rights, the right to exercise the Rights will terminate and the only right of the holders of Rights will be to receive the Redemption Price.

The Rights Agreement further provides that if the Company receives a Qualifying Offer (that has not been terminated and continues to be a Qualifying Offer for the period hereinafter described) and the Board of Directors has not redeemed the outstanding Rights, exempted such Qualifying Offer from the terms of the Rights Agreement or called a special meeting of the stockholders for the purpose of voting on whether or not to exempt such Qualifying Offer from the terms of the Rights Agreement, then stockholders representing at least 10% of the shares of Common Stock then outstanding may request that the Board of Directors call a special meeting of stockholders to vote to exempt the Qualifying Offer from the operation of the Rights Agreement, such notice to be delivered not earlier than ninety (90), nor later than one hundred twenty (120), Business Days following the commencement of such offer. The Board of Directors must then call and hold such a meeting to vote on exempting such offer from the terms of the Rights Agreement by the ninetieth (90th) Business Day following receipt of the stockholder demand for the meeting; provided that such period may be extended if, prior to the vote, the Company enters into an agreement (that is conditioned on the approval by the holders of a majority of the outstanding shares of Common Stock) with respect to a merger, recapitalization, share exchange, or a similar transaction involving the Company or the direct or indirect acquisition of more than 50% of the Company’s consolidated total assets (a “Definitive Acquisition Agreement”), until the time of the meeting at which the stockholders will be asked to vote on the Definitive Acquisition Agreement. If no Acquiring Person has emerged, the offer continues to be a Qualifying Offer and stockholders representing a majority of the shares of Common Stock represented at the meeting at which a quorum is present vote in favor of redeeming the rights, then such Qualifying Offer shall be deemed exempt from the Rights Agreement on the date that the vote results are certified. If no Acquiring Person has emerged and no special meeting is held by the date required, the Rights will be redeemed at the close of business on the tenth (10th) Business Day following that date.

A Qualifying Offer, in summary terms, is an offer determined by the Board of Directors to have each of the following characteristics which are generally intended to preclude offers that are coercive, abusive, or clearly illegitimate:

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Any offers that have cash as all or partial consideration are subject to further conditions for qualification as “qualifying offers,” as set forth in the Rights Agreement. These conditions generally

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require assurance that the offer is fully financed and that the offeror has sufficient committed resources to consummate the offer. Any offers that have acquiror common stock as all or partial consideration are subject to further conditions for qualification as “qualifying offers,” as set forth in the Rights Agreement. These conditions generally require certain safeguards regarding, and access to, information about the acquiror to allow an informed determination as to the value and risks of the stock, including safeguards against developments that adversely affect the value of the stock, that the acquiror’s stock (which may not have subordinated voting rights or have ownership be heavily concentrated in one person or group) is listed on a national exchange, that the acquiror meets certain seasoned issuer standards under the Securities Act of 1933, and that no acquiror stockholder approval of the issuance of the consideration to the Company stockholders is necessary after commencement of the offer.

The terms of the Rights may be amended by the Board of Directors of the Company without the consent of the holders of the Rights, except that from and after such time as any person becomes an Acquiring Person no such amendment may adversely affect the interests of the holders of the Rights (other than the Acquiring Person and its Affiliates and Associates).

Until a Right is exercised, the holder thereof, as such, will have no rights as a stockholder of the Company, including, without limitation, the right to vote or to receive dividends.

This summary description of the Rights does not purport to be complete and is qualified in its entirety by reference to the Rights Agreement, which is filed as an Exhibit hereto and incorporated herein by reference.

Effective April 25, 2012, the Board of Directors of the Company filed a Certificate of Designations with the Secretary of State of the State of Delaware which designated Series A Junior Participating Preferred Stock as a series of the Preferred Stock of the Company with the rights, preferences and privileges as further described above under “Item 3.03 Material Modification to Rights of Securities Holders.” As of the date of this Current Report on Form 8-K, none of the shares of Series A Junior Participating Preferred Stock have been issued. The description of the Series A Junior Participating Preferred Stock is qualified in its entirety by reference to the Certificate of Designations filed with the Secretary of State of the State of Delaware, a copy of which is attached as Exhibit 3.1 to this Current Report on Form 8-K and is incorporated by reference herein.

(d) Exhibits

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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