O
- OASIS
- OASIS for Advisors
- OASIS for Guests
- Objectivist Club, USC
- Obstetrics and Gynecology, Department of
- OCAAA--Oversight Committee for Athletic Academic Affairs
- Occupational Therapy
- Office of Budget and Planning
- Office of Campus Activities
- Office of Compliance
- Office of International Services
- Office of Overseas Studies
- Office of Postdoctoral Affairs, Keck School of Medicine
- Office of the General Counsel
- Office of the President
- OJR: Online Journalism Review
- ONE Institute and Archives
- One Stop Problem Solving
- ONEUSC
- Online Health Information
- Ophthalmology, Department of
- OPRS - Office for the Protection of Research Subjects
- Orange County Center
- Order of the Torch (Mr. and Ms. USC)
- Orientation Office, USC
- OTiS - USC's Online Timekeeping System
- Otolaryngology/Head and Neck Surgery, Department of
- Ovid