Sixth Street Specialty Lending Inc

Evaluation of Disclosure Controls and Procedures. As of the end of the period covered by this Annual Report, we carried out an evaluation, under the supervision and with the participation of our management, including our Chief Executive Officer and Chief Financial Officer, of the effectiveness of the design and operation of our disclosure controls and procedures (as defined in Rule 13a-15 under the Exchange Act). Based on that evaluation, our Chief Executive Officer and Chief Financial Officer have concluded that our current disclosure controls and procedures are effective in timely alerting them to material information relating to us that is required to be disclosed by us in the reports we file or submit under the Exchange Act.

Management’s Report on Internal Control Over Financial Reporting. Our management is responsible for establishing and maintaining adequate internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) of the Exchange Act). Under the supervision and with the participation of management, including the Chief Executive Officer and Chief Financial Officer, we conducted an evaluation of the effectiveness of our internal control over financial reporting based on the criteria established in Internal Control—Integrated Framework (2013)issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 COSO Framework). Based on our evaluation under the framework in Internal Control—Integrated Framework, management concluded that our internal control over financial reporting was effective as of December 31, 2023.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Attestation Report of the Independent Registered Public Accounting Firm. Our independent registered public accounting firm, KPMG LLP, has issued an audit report on the effectiveness of our internal control over financial reporting, which is set forth under the heading “Report of Independent Registered Public Accounting Firm” on page F-2.

Changes in Internal Control over Financial Reporting. There have been no changes in our internal control over financial reporting that occurred during our most recently completed fiscal quarter that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.