v3.26.1
Document and Entity Information
May 05, 2026
Cover [Abstract]  
Amendment Flag false
Entity Central Index Key 0001508655
Document Type 8-K
Document Period End Date May 05, 2026
Entity Registrant Name Sixth Street Specialty Lending, Inc.
Entity Incorporation State Country Code DE
Entity File Number 001-36364
Entity Tax Identification Number 27-3380000
Entity Address, Address Line One 2100 McKinney Avenue
Entity Address, Address Line Two Suite 1500
Entity Address, City or Town Dallas
Entity Address, State or Province TX
Entity Address, Postal Zip Code 75201
City Area Code (469)
Local Phone Number 621-3001
Written Communications false
Soliciting Material false
Pre Commencement Tender Offer false
Pre Commencement Issuer Tender Offer false
Security 12b Title Common Stock, par value $0.01 per share
Trading Symbol TSLX
Security Exchange Name NYSE
Entity Emerging Growth Company false