CSK may refer to:
- Chan Sui Ki (La Salle) College, an Anglo-Chinese Boys' high school in Hong Kong
- CSK Holdings Corporation, a Japanese IT company
- Chennai Super Kings, an Indian Premier League franchise
- ICAO airline designator for Flightcraft in the United States
- Coretta Scott King (1927-2006), an American civil rights activist
- CSK, National Rail station code for Calstock railway station, Cornwall, England
- Country code of the former country of Czechoslovakia
- Its currency, the Czechoslovak koruna
- C-src tyrosine kinase, an enzyme
- CSK Auto, a subsidiary of O'Reilly Auto Parts
- Commander of the Order of the Star and Key of the Indian Ocean