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) January 22, 2013

RPM INTERNATIONAL INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (330) 273-5090

(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 (see General Instruction A.2. below):

On January 22, 2013, the Board of Directors of RPM International Inc. (the “Company”) appointed Salvatore D. Fazzolari, age 60, to Class II of the Company’s Board of Directors. Mr. Fazzolari replaces James A. Karman, who retired from the Board at the Company’s Annual Meeting of Stockholders on October 4, 2012. Mr. Fazzolari’s term will expire at the Company’s Annual Meeting of Stockholders in 2015, at which time he will stand for re-election to the Board by the Company’s stockholders. He will serve on the Board’s Audit Committee. Mr. Fazzolari is the former chairman, president and chief executive officer of Harsco Corporation, a $3.3 billion diversified global industrial company that is based in Camp Hill, Pennsylvania, and is traded on the New York Stock Exchange.

Mr. Fazzolari’s compensation for his service as a director will be consistent with that of the Company’s other directors who are not employees or consultants of the Company, as described in the Company’s definitive proxy statement filed with the Securities and Exchange Commission on August 29, 2012 under the caption “Director Compensation,” which portion of such proxy statement is incorporated herein by reference.

In connection with his appointment as a director, the Company and Mr. Fazzolari entered into an indemnification agreement effective as of January 22, 2013. The indemnification agreement is the same as the indemnification agreements the Company has entered into with each of its directors and executive officers. The indemnification agreement requires the Company to indemnify Mr. Fazzolari to the fullest extent permitted by law against all expenses, judgments, settlements, fines and penalties, actually and reasonably incurred in the defense or settlement of any civil, criminal, administrative or investigative action brought against him by reason of his relationship with the Company, including third-party claims and proceedings brought by or in the right of the Company, subject to certain exceptions. The rights provided to Mr. Fazzolari under the indemnification agreement are in addition to any other rights he may be entitled to under the Company’s Amended and Restated Certificate of Incorporation or Amended and Restated By-laws, the General Corporation Law of the State of Delaware or otherwise. The description of the indemnification agreement set forth in this Item 5.02 is not complete and is qualified in its entirety by reference to the full text of the form of indemnification agreement. The form of indemnification agreement between the Company and each of its directors and executive officers was filed as Exhibit 10.14 to the Company’s Quarterly Report on Form 10-Q for the quarter ended November 30, 2002 and is incorporated herein by reference.

There are no arrangements or understandings between Mr. Fazzolari and any other persons pursuant to which Mr. Fazzolari was selected as a director. There have been no transactions involving the Company or any of its subsidiaries in which Mr. Fazzolari has or will have a direct or indirect material interest that are required to be disclosed by Item 404(a) of Regulation S-K.

On January 22, 2013, the Company issued a press release announcing Mr. Fazzolari’s appointment to the Company’s Board of Directors. A copy of the press release is attached hereto as Exhibit 99.1 and furnished herewith.

(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.

Exhibit Index