| Abbreviation | Definition |
|---|---|
| OACS | Oakland Avenue Charter School |
| OAHS | Oxford Area High School |
| OAS | Olympic Archery in Schools |
| OAS | Open Alternative School |
| OASD | Oconomowoc Area School District |
| OASD | Ontonagon Area School District |
| OASD | Oshkosh Area School District |
| OASD | Oxford Area School District |
| OASPA | Open Access Scholarly Publishers Association |
| OASR | Outreach and School Relations |
| OBBS | Oxford Brookes Business School |
| OBH | Oak Bay High School |
| OBHS | Oak Bay High School |
| OBHS | Old Bridge High School |
| OBHS | Old Buckenham High School |
| OBHS | Olive Branch High School |
| OBHS | Ondo Boys High School |
| OBHS | Open Bible High School |
| OBHS | Orange Beach High School |
| OBHS | Otago Boys' High School |