Tsk or TSK may refer to:
- Dental click, as in an interjection used in English to express disapproval, often spelled as "tsk" or "tut"
- The Turkish Armed Forces, (Turkish: Türk Silahlı Kuvvetleri)
- Traffic Security Key, used to control spread spectrum radios; see List of cryptographic key types
- Tiger Schulmann's Karate, now Tiger Schulmann's Mixed Martial Arts
- In Halo: Combat Evolved, an abbreviation for Three Shot Kill
- The Sleuth Kit, collection of computer forensics-related tools
- ICAO code of airline Tomskavia
- San-in Chūō Television Broadcasting, a Japanese TV station
- Treasury of Scripture Knowledge – a Bible Concordance developed by R. A. Torrey