CUO may refer to:
- Cadet Under Officer rank in Senior Division & Senior Women Army wings of the National Cadet Corps (India)
- CuO - Copper(II) oxide
- COU is the ICAO airline designator for Aerocuahonte, Mexico
- Compaq Users Organisation
- Cadet Under Officer in the Australian Army Cadets
- Cadet Under Officer in the Australian Air Force Cadets
Refer also:
CUO-abbreviation of Chief Underwriting Officer used in insurance company or top underwriting occupation of an insurance company