| Abbreviation | Definition |
|---|---|
| OPE | Office of Postsecondary Education |
| OPENU | The Open University |
| OPG | Office of Projects and Grants |
| OPI | Oral Proficiency Interview |
| OPME | Officer Professional Military Education |
| OPP | open public pool |
| OPRP | Office of Physical Resources Planning |
| OPRP | Office of Physical Resources & Planning |
| OPRR | Office for Protection for Research Risks |
| OPS | Ohio Photography School |
| OPSA | Office of Professional School Advising |
| OPSA | Oklahoma Political Science Association |
| OPSA | Otago Polytechnic Students' Association |
| OPSE | OPtical Science and Engineering courses |
| OPSK | Old Pratumnuk SuanKularb |
| OPSM | Operations Management classes |
| OPSN | Organization of PhD Students in Nursing |
| OPSU | Oklahoma Panhandle State University |
| OPU | Osaka Prefecture University |
| OPUS | Oberlin Project for Unified Systems |