Golub Capital BDC (GBDC) 8-KEntry into a Material Definitive Agreement

Exhibit 5.1

December 5, 2023

Golub Capital BDC, Inc.

200 Park Avenue, 25^th Floor

New York, NY 10166

Ladies and Gentlemen:

We have acted as counsel to Golub Capital BDC, Inc., a Delaware corporation (the “Company”), in connection with the public offering of $450,000,000 in aggregate principal amount of the Company’s 7.050% unsecured notes due 2028 (the “Notes”), pursuant to the Company’s registration statement on Form N-2 (File No. 333-265509) (the “Registration Statement”) filed by the Company with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), which became automatically effective upon filing with the Commission, pursuant to Rule 462(e) under the Securities Act, on June 9, 2022, relating to the public offering of securities of the Company that may be offered by the Company from time to time as set forth in the prospectus dated June 9, 2022, which was included in the Registration Statement, and which forms a part of the Registration Statement (the “Prospectus”), and as may be set forth from time to time in one or more supplements to the Prospectus. This opinion letter is rendered in connection with such public offering of the Notes, as described in the Prospectus and a prospectus supplement dated November 30, 2023 (the “Prospectus Supplement”). All of the Notes are to be sold by the Company as described in the Registration Statement and related Prospectus and Prospectus Supplement.

The Notes will be issued pursuant to the indenture, dated October 2, 2020, entered into between the Company and U.S. Bank Trust Company, National Association (as successor in interest to U.S. Bank National Association), as trustee (the “Trustee”), as supplemented by a fourth supplemental indenture, dated December 5, 2023, entered into between the Company and the Trustee (collectively, the “Indenture”).

As counsel to the Company, we have reviewed the Registration Statement, the Prospectus and the Prospectus Supplement, and have examined the originals or copies of the following:

Eversheds Sutherland (US) LLP is part of a global legal practice, operating through various separate and distinct legal entities, under Eversheds Sutherland.  For a full description of the structure and a list of offices, please visit www.eversheds-sutherland.com.

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With respect to such examination and our opinion expressed herein, we have assumed, without any independent investigation or verification, (i) the genuineness of all signatures on all documents submitted to us for examination, (ii) the legal capacity of all natural persons, (iii) the authenticity of all documents submitted to us as originals, (iv) the conformity to original documents of all documents submitted to us as conformed or reproduced copies and the authenticity of the originals of such copied documents, (v) that all certificates issued by public officials have been properly issued, (vi) the accuracy and completeness of all corporate records made available to us by the Company, (vii) that the Indenture will be a valid and legally binding obligation of the parties thereto (other than the Company), and (viii) that at the time of issuance of the Notes, after giving effect to such issuance, the Company will be in compliance with Section 18(a)(1)(A) of the Investment Company Act of 1940, as amended (the “1940 Act”), giving effect to Section 61(a) of the 1940 Act.

This opinion letter has been prepared, and should be interpreted, in accordance with customary practice followed in the preparation of opinion letters by lawyers who regularly give, and such customary practice followed by lawyers who on behalf of their clients regularly advise opinion recipients regarding, opinion letters of this kind.

As to certain matters of fact relevant to the opinions in this opinion letter, we have relied upon certificates and/or representations of officers of the Company. We also have relied upon certificates and confirmations of public officials. We have not independently established the facts, or in the case of certificates or confirmations of public officials, the other statements, so relied upon.

The opinion set forth below is limited to the contract laws of the State of New York, as in effect on the date hereof, and we express no opinion with respect to any other laws of the State of New York or the laws of any other jurisdiction. Without limiting the preceding sentence, we express no opinion as to any state securities or broker-dealer laws or regulations thereunder relating to the offer, issuance or sale of the Notes.

On the basis of and subject to the foregoing, and subject to the all of the assumptions, qualifications and limitations set forth in this opinion letter, we are of the opinion that, when the Notes are duly executed and delivered by duly authorized officers of the Company and duly authenticated by the Trustee, all in accordance with the provisions of the Indenture, and delivered to the purchasers thereof against payment of the agreed consideration therefor, the Notes will constitute valid and legally binding obligations of the Company, enforceable against the Company in accordance with their terms, except as such enforceability may be limited by applicable bankruptcy, insolvency, reorganization, receivership, moratorium, fraudulent conveyance, and other similar laws affecting the rights and remedies of creditors generally and by general principles of equity (including without limitation the availability of specific performance or injunctive relief and the application of concepts of materiality, reasonableness, good faith and fair dealing), regardless of whether considered in a proceeding at law or in equity.

The opinions expressed in this opinion letter are (a) strictly limited to the matters stated in this opinion letter, and without limiting the foregoing, no other opinions are to be inferred, and (b)  only as of the date of this opinion letter, and we are under no obligation, and do not undertake, to advise the Company or any other person or entity either of any change of law or fact that occurs, or of any fact that comes to our attention, after the date of this opinion letter, even though such change or such fact may affect the legal analysis or a legal conclusion in this opinion letter.

We hereby consent to the filing of this opinion letter as an exhibit to the Company’s Current Report on Form 8-K to be filed with the Commission on the date hereof for incorporation by reference in the Registration Statement and to the reference to our firm in the “Legal Matters” section in the Registration Statement, the Base Prospectus and Prospectus Supplement. We do not admit by giving this consent that we are in the category of persons whose consent is required under Section 7 of the Securities Act.