CU, Cu, or cu may refer to:
- Copper, a chemical element
- The ISO 639-1 code for Old Church Slavonic
- The cu (=call unix) remote login command used on unix-like computing systems
- "See you" in e-mail shorthand
- The Latin abbreviation for colitis ulcerosa, an inflammatory bowel disease (IBD).
In mathematics, science and medicine:
- Control unit (disambiguation)
- CU (Powerline), an HVDC-powerline in the USA
- Cube/cubic in a variety of English Imperial units and United States customary units (cubic inch, cubic foot, etc.).
- Cumulus clouds
- Cellulase Unit
- Callous and unemotional traits
Referencing a place:
- .cu, Cuba's top-level domain country code
- Old Church Slavonic: ISO 639 alpha-2 language code
- Cuba, ISO 3166, FIPS Pub 10-4 and obsolete NATO digram
In film making:
- Close-up
As a company or organization:
- ChristianUnion, a political party in the Netherlands
- Consumers Union
- Credit union
- Cubana, an IATA airline designator
- Christian Union (students), a university or college student Christian group
As a university:
- Bangladesh
- Chittagong University
- Canada
- Carleton University, Ottawa
- Concordia University (Montreal)
- Czech Republic
- Charles University, Prague
- Egypt
- Cairo University
- Germany
- Catholic University of Eichstätt-Ingolstadt
- Hong Kong
- Chinese University of Hong Kong
- India
- University of Calcutta
- Nigeria
- Covenant University
- Thailand
- Chulalongkorn University
- United Kingdom
- Cardiff University
- Cranfield University
- Coventry University
- University of Cambridge
- United States
- Cameron University (US)
- Cedarville University (US)
- Chapman University (US)
- Clarkson University (US)
- Clemson University (US)
- Colgate University (US)
- Columbia University (US)
- Cornell University (US)
- Cornerstone University (US)
- Creighton University (US)
- University of Colorado at Boulder (US)
- University of Colorado system (US)