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 the earliest event reported): December 26, 2012

UNIFIED GROCERS, INC.

(Exact name of registrant as specified in its charter)

5200 Sheila Street, Commerce, CA 90040

(Address of principal executive offices) (Zip Code)

(323) 264-5200

(Registrant’s telephone number, including area code)

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:

On December 26, 2012, Unified Grocers, Inc. (the “Company”) entered into the fifth amendment (“Fifth Amendment”) of the Company’s Amended and Restated Note Purchase Agreement, as amended (the “Notes Agreement”), with the current noteholders and John Hancock Life Insurance Company (U.S.A.), acting in its capacity as collateral agent for the current noteholders. The Fifth Amendment raises the maximum Indebtedness to Consolidated EBITDAP Ratio (the “Indebtedness Ratio”) of the Company allowed by the financial covenants in the Notes Agreement for the fiscal quarter ending December 29, 2012 to be no higher than 4.0 to 1 (previously, the maximum Indebtedness Ratio for such fiscal quarter allowed under the Notes Agreement was no higher than 3.75 to 1). For subsequent fiscal quarters, the Indebtedness Ratio remains the same as before the Fifth Amendment.

On December 29, 2012, the Company entered into the third amendment (the “Third Amendment”) of the Credit Agreement dated as of October 8, 2010, as amended (the “Credit Agreement”), among the Company, the lenders party thereto and Wells Fargo Bank, National Association, as administrative agent. The Third Amendment raises the Consolidated Total Funded Debt to EBITDAP Ratio (the “Debt Ratio”) of the Company allowed by the financial covenants in the Credit Agreement for the fiscal quarter ending December 29, 2012 to be no higher than 4.0 to 1 (previously, the maximum Debt Ratio for such fiscal quarter allowed under the Credit Agreement was 3.5 to 1). For subsequent fiscal quarters, the Debt Ratio remains as before the Third Amendment.

Exhibits – Incorporation by Reference

A copy of the Fifth Amendment and Third Amendment are attached hereto as Exhibit 99.1 and Exhibit 99.2, respectively, and are incorporated herein by this reference. The foregoing description of the Fifth Amendment and Third Amendment does not purport to be complete and is qualified in their entirety by reference to the exhibits.

(d) Exhibits

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.