CSAR may refer to:
- Alternate spelling of the title of nobility, Tsar
- Center for the Simulation of Advanced Rockets
- Central South African Railways
- Combat search and rescue
- Cosa succederà alla ragazza, a music album by Lucio Battisti
- Comité secret d'action révolutionnaire, a French anti-communist group better known as La Cagoule
- Caris Spatial Archive, a file format for storing bathymetry data