| AOPA | Agricultural Operation Practices Act 
| Others |
| AOPA | Aircraft Owners and Pilots Association
| Others |
| AOPA | Airplane Owners and Pilots Association
| Others |
| AOPA | American Orthotic & Prosthetic Association
| Others |
| AOPA | American Orthotic And Prosthetic
| Others |
| AOPA | American Orthotic and Prosthetic Association
| Others |
| AOPA | American Orthotic Prosthetic Association
| Others |
| AOPA | Aspect Oriented Program Analysis
| Others |
| AOPA | Australian Orthotic Prosthetic Association Inc.
| Others |
| AOPA | The Aircraft Owners and Pilots Association
| Others |