| Acronym | Definition |
|---|
| OSJ | Optical Society of Japan (Japan Society of Applied Physics) |
| OSJ | Office of Supervisory Jurisdiction (SEC) |
| OSJ | Orchestra of St John's (London, UK) |
| OSJ | Opera San Jose (San Jose, California) |
| OSJ | Order of St. John of Jerusalem (Knights of Malta) |
| OSJ | Oblates of St. Joseph (religious order) |
| OSJ | Ocean Science Journal (Korea) |
| OSJ | Open Source Japan |
| OSJ | Order of St. James (Christian group) |
| OSJ | Open Stub J-Pole (amateur radio antenna) |
| OSJ | Order of the Knights Hospitaller of St. John of Jerusalem, Palestine, Rhodes, and Malta |