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: August 8, 2013

(Date of earliest event reported)

WhiteHorse Finance, Inc.

(Exact name of registrant as specified in its charter)

(305) 379-2322

(Registrant’s telephone number, including area code)

Not Applicable

(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 August 13, 2013, WhiteHorse Finance, Inc. (the “Company”) issued a press release announcing its second quarter financial results. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

The information in Item 2.02 of this Current Report on Form 8-K, including Exhibit 99.1 furnished herewith, is being furnished and shall not be deemed “filed” for any purpose of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of such Section. The information in this Current Report on Form 8-K shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Forward-Looking Statements

This Current Report on Form 8-K, including Exhibit 99.1 furnished herewith, may contain “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Statements other than statements of historical facts included in this Current Report on Form 8-K may constitute forward-looking statements and are not guarantees of future performance or results and involve a number of risks and uncertainties. Actual results may differ materially from those in the forward-looking statements as a result of a number of factors, including those described from time to time in filings with the Securities and Exchange Commission. The Company undertakes no duty to update any forward-looking statement made herein. All forward-looking statements speak only as of the date of this Current Report on Form 8-K.

On August 8, 2013, the Company held its annual meeting of stockholders (the “Annual Meeting”). At the Annual Meeting, the Company’s stockholders approved two proposals. The issued and outstanding shares of stock of the Company entitled to vote at the Annual Meeting consisted of 14,965,624 shares of common stock outstanding on the record date, June 13, 2013. The final voting results from the Annual Meeting were as follows:

Proposal 1. To elect one Class I director of the Company who will serve for a term of three years or until his successor is duly elected and qualifies.

Proposal 2. To ratify the selection of Crowe Horwath LLP to serve as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2013.

Item 9.01. Financial Statements and Exhibits

(d) Exhibits

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.