CTU may refer to:
- Catholic Theological Union
- Chengdu Shuangliu International Airport (IATA airport code)
- Clinical trials unit
- Colorado Technical University
- Conservative Trade Unionists
- New Zealand Council of Trade Unions
- Czech Technical University in Prague
- Cebu Technological University
- Chicago Teachers Union
- Counter Terrorist Unit, a fictional United States government anti-terrorism agency in the television series 24
- Cargo Transport Unit, a transport container.