| Abbreviation | Definition |
|---|---|
| OSPA | Oregon School Personnel Association |
| OSPRA | Office of School Personnel Review and Accountability |
| OSPS | Old Saybrook Public Schools |
| OSR | Old School Renaissance |
| OSR | Old School Revival |
| OSR | Old School Roleplaying |
| OSR | Old School Rules |
| OSR | Ontario Student Record |
| OSRS | Old School RuneScape |
| OSRS | Old School Runescape Sometimes |
| OSS | Old School Sausages |
| OSS | Ontario Secondary Schools |
| OSSA | Oregon School Ski Association |
| OSSC | Ohio State School of Cosmetology |
| OSSCEXAM | Oriented Secondary School Certificate |
| OSSD | Ocean Springs School District |
| OSSD | Ontario Secondary School Diploma |
| OSSI | Office of School Support and Improvement |
| OSSI | Office of System and School Improvement |
| OSSI | Oklahoma School Security Institute |