| ORSA | Oak Ridge Sportsmen's Association 
| Others |
| ORSA | Occupational Road Safety Alliance
| Others |
| ORSA | Off Road Severe Application
| Others |
| ORSA | Office of Research Services and Administration
| Others |
| ORSA | Officine Realizzazione Sarde Automobili
| Others |
| ORSA | Ohio Recreational Sports Association
| Others |
| ORSA | Operations Research and Systems Analysis
| Others |
| ORSA | Operations Research Society of America
| Others |
| ORSA | Operations Research Systems Analysis
| Others |
| ORSA | Operations Research/Systems Analysis
| Others |
| ORSA | Operations Research/Systems Analyst
| Others |
| ORSA | Orbit Reconstruction Simulation and Analysis
| Others |
| ORSA | Outdoor Recreation Satellite Account
| Others |
| ORSA | Own Risk and Solvency Assessment
| Others |
| ORSA | Own Risk Solvency Assessment
| Others |
| ORSA | Oxacillin Resistant Staph aureus
| Others |
| ORSA | oxacillin resistant Staphylococcus aurous
| Others |