OCU may mean:
- Ohio Christian University
- Oklahoma City University
- Operational Conversion Unit, a unit in an air force
- Operational Command Unit, a unit in a police force
- Operator Control Unit, a hardware or software control interface for an automated system
- One Cohesive Unit, a nickname for Annville-Cleona's men's high school soccer team
- Organized Chaos Unit, a unit of armed Citizens
- Osaka City University, a public university in Osaka, Japan