Exhibit 32.1

CERTIFICATION OF PRINCIPAL EXECUTIVE OFFICER, SECTION 906

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

I, Aren C. LeeKong, the Chief Executive Officer (Principal Executive Officer) of Carlyle Secured Lending, Inc. (the “Company”), hereby certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

•the Form 10-K of the Company for the year ended December 31, 2023 as filed with the Securities and Exchange Commission on the date hereof (the “Form 10-K”), fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)); and

•the information contained in the Form 10-K fairly presents, in all material respects, the financial condition and results of operations of the Company.

Dated: February 26, 2024

/s/ Aren C. LeeKong

Aren C. LeeKong
President and Chief Executive Officer
(Principal Executive Officer)

*The foregoing certification is being furnished solely pursuant to 18 U.S.C. Section 1350 and is not being filed as part of the Report or as a separate disclosure document.