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): March 10, 2014

CALUMET SPECIALTY PRODUCTS PARTNERS, L.P.

(Exact name of registrant as specified in its charter)

2780 Waterfront Pkwy E. Drive

Suite 200

Indianapolis, Indiana 46214

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code (317) 328-5660

(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:

On March 10, 2014, Calumet Specialty Products Partners, L.P. (the “Partnership”) and Calumet GP, LLC (the “General Partner”) entered into an Equity Placement Agreement (the “Agreement”) with Barclays Capital Inc., Merrill Lynch, Pierce, Fenner & Smith Incorporated, Goldman, Sachs & Co., J.P. Morgan Securities LLC, MLV & Co. LLC and RBC Capital Markets, LLC (each, a “Manager” and collectively, the “Managers”). Pursuant to the terms of the Agreement, the Partnership may sell from time to time through the Managers, as the Partnership’s sales agents, the Partnership’s common units representing limited partner interests having an aggregate offering price of up to $300,000,000 (the “Units”). Sales of the Units, if any, will be made by means of ordinary brokers’ transactions on the NASDAQ Global Select Market or as otherwise agreed by the Partnership and one or more of the Managers.

Under the terms of the Agreement, the Partnership may also sell Units from time to time to any Manager as principal for its own account at a price to be agreed upon at the time of sale. Any sale of Units to any Manager as principal would be pursuant to the terms of a separate terms agreement between the Partnership and such Manager.

The Units will be issued pursuant to the Partnership’s shelf registration statement on Form S-3 (Registration No. 333-188654).

The summary of the Agreement in this report does not purport to be complete and is qualified by reference to the full text of the Agreement, a copy of which is filed as Exhibit 1.1 to this Current Report on Form 8-K, and is incorporated herein by reference.

(d) Exhibits.

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Signature

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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Exhibit Index

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