The acronym CSU may refer to:
- Constant speed unit - a mechanical device on an aircraft propeller that regulates engine speed by automatically changing pitch
- Channel Service Unit - a WAN equivalent of a network interface card
- Christian Social Union of Bavaria (Christlich-Soziale Union in Bayern), a political party in Bavaria, Germany
- Crime Scene Unit - in some police groups this refers to crime scene investigators who respond to a crime scene
- Care and Separation Unit - the name given to solitary confinement in some prisons in the United Kingdom
- C Start Up - in computing, the initial start up code for compiled C (and C-based languages)
See also CRT for C Run-Time
- ČSÚ (Český statistický úřad), Czech Statistical Office
- CSU is the ICAO airline designator for Chari Aviation Services, Chad
Read more about CSU: Universities and University Systems