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): December 3, 2012

Applied Micro Circuits Corporation

(Exact Name of Registrant as Specified in Charter)

215 Moffett Park Drive, Sunnyvale, California 94089

(Address of Principal Executive Offices)

(408) 542-8600

(Registrants telephone number, including area code)

N/A

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

Check the appropriate box below if the Form 8-K is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Item 2.05. Costs Associated with Exit or Disposal Activities.

On December 3, 2012, the board of directors of Applied Micro Circuits Corporation (the “Company”) approved a restructuring plan to reorganize the Company’s operations and reduce its workforce and related operating expenses. The plan includes eliminating job redundancies and reducing the Company’s current workforce by approximately 70 employees, or approximately 10%. As of the date of the filing of this Current Report on Form 8-K, the Company has initiated the reduction in its workforce. The Company expects to incur cash expenditures of approximately $1.2 million to $1.4 million during the current fiscal year ending March 31, 2013 for employee severances. The Company anticipates that the restructuring plan will reduce ongoing headcount expenses by approximately $8.0 million to $9.0 million annually and other additional operational expenses by $4.0 million to $5.0 million annually.

This current report on Form 8-K contains forward-looking statements, including, but not limited to, statements regarding the expected costs of the Company’s restructuring plan and the anticipated reduction of ongoing operating expenses to the Company as a result of the plan. These forward looking statements are only predictions based on current information and expectations and are subject to certain risks and uncertainties, including, but not limited to, the Company’s ability to implement the restructuring plan to the extent currently anticipated, possible changes in the size and components of the operating expense reductions, the impact of personnel reductions on product development efforts, the Company’s ability to project accurately cost savings and changes from the plan and general economic conditions. More information about potential factors that could affect the Company’s business and financial results is included in the “Risk Factors” set forth in the Company’s Annual Report on Form 10-K for the year ended March 31, 2012, and the Company’s other filings with the Securities and Exchange Commission. Actual results could differ materially, as a result of such factors, from those set forth in the forward- looking statements. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this current report on Form 8-K. All forward-looking statements are qualified in their entirety by this cautionary statement.

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.