O
- OC - Oklahoma Christian University
- OCC - Orange Coast College
- OCU - Oklahoma City University
- ODU - Ohio Dominican University, Old Dominion University
- OIT - Oregon Institute of Technology
- Ole Miss - University of Mississippi
- ONU - Ohio Northern University
- ORU - Oral Roberts University
- OSU - The Ohio State University, Oklahoma State University, Oregon State University
- OU - Oakland University, Ohio University, University of Oklahoma
- Oxy - Occidental College
Read more about this topic: List Of Colloquial Names For Universities And Colleges In The United States