UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 10-Q/A

Amendment No. 1

(Mark One)

For the Quarterly Period Ended June 30, 2012

OR

For the Transition Period from             to            

Commission File Number 001-33368

Glu Mobile Inc.

(Exact name of the Registrant as Specified in its Charter)

45 Fremont Street, Suite 2800

San Francisco, California 94105

(Address of Principal Executive Offices, including Zip Code)

(415) 800-6100

(Registrant’s Telephone number, including Area Code)

Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the Registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the Registrant was required to submit and post such files).    Yes  x    No  ¨

Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  x

Shares of Glu Mobile Inc. common stock, $0.0001 par value per share, outstanding as of August 2, 2012: 65,155,557.

EXPLANATORY NOTE

Glu Mobile Inc. (“Glu”) is filing this Amendment No. 1 (this “Amendment”) to its quarterly report on Form 10-Q for the quarter ended June 30, 2012, originally filed with the Securities and Exchange Commission on August 9, 2012 (the “Original Filing”), for the sole purpose of amending Item 6 of Part II to re-file Exhibit 10.01 to the Original Filing. Exhibit 10.01 is a License Agreement, dated as of March 31, 2012, that Glu entered into with Atari, Inc. (“Atari”) in connection with Glu’s acquisition of the Deer Hunter brand assets from Atari. Exhibit 10.01 to the Original Filing, portions of which for which we have requested confidential treatment, inadvertently omitted Exhibit B, which is a nondisclosure agreement between Glu and Atari. Glu is re-filing Exhibit 10.01 in its entirety to correct this error.

No changes have been made to the financial statements or any other disclosures contained in the Original Filing. This Amendment does not reflect subsequent events occurring after the filing date of the Original Filing or modify or update in any way disclosures made in the Original Filing.

PART II. OTHER INFORMATION

The exhibits listed on the Exhibit Index (following the Signatures section of this Amendment) are incorporated by reference into this Item 6.

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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 thereunto duly authorized.

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EXHIBIT INDEX

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