UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 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 18, 2014

GOLUB CAPITAL BDC, INC.

(Exact name of Registrant as Specified in Its Charter)

Registrant’s telephone number, including area code: (312) 205-5050

(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 December 18, 2014, Golub Capital BDC Funding LLC (“Funding”), a wholly owned subsidiary of Golub Capital BDC, Inc. (the “Company”), entered into an amended and restated senior secured revolving credit facility (the “Amended and Restated Credit Facility”) with Wells Fargo Securities, LLC, as administrative agent, and Wells Fargo Bank, N.A., as lender.

Funding entered into the Amended and Restated Credit Facility to allow for the addition of a second lender under the facility. There were no other material changes to the terms of the Amended and Restated Credit Agreement.

As previously disclosed, the Amended and Restated Credit Facility is secured by all of the assets held by Funding, and the Company has pledged its interests in Funding as collateral to Wells Fargo Bank, N.A., as the collateral agent, to secure the obligations of the Company as the transferor and servicer under the Amended and Restated Credit Facility. Borrowing under the Credit Facility remains subject to the leverage restrictions contained in the Investment Company Act of 1940, as amended.

The description above is only a summary of the material provisions of the Amended and Restated Credit Facility and is qualified in its entirety by reference to a copy of the Amended and Restated Credit Facility, which is filed as Exhibit 10.1 to this current report on Form 8-K.

10.1         Amended and Restated Loan and Servicing Agreement, dated as of December 18, 2014, by and among Golub Capital BDC Funding LLC, as the Borrower; Golub Capital BDC, Inc., as Transferor and Servicer; Wells Fargo Securities, LLC, as the Administrative Agent; the lenders from time to time party thereto; the lender agents from time to time party thereto; and Wells Fargo Bank, N.A., as the Collateral Agent, the Account Bank, and the Collateral Custodian (amending the Loan and Servicing Agreement, dated as of July 21, 2011).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, Golub Capital BDC, Inc. has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.