| Abbreviation | Definition |
|---|---|
| ANTP | Association of National TheatreArts Practitioners (Nigeria) |
| AOA | American Optometric Association |
| AOA | American Osteopathic Association |
| AOA | American Ostrich Association |
| AOA | Association of Otolaryngology Administrators |
| AOAC | Association of Official Analytical Chemists |
| AOAD | Arab Organization for Agricultural Development |
| AOAO | American Osteopathic Academy of Orthopedics |
| AOBNM | American Osteopathic Board of Nuclear Medicine |
| AOBP | Association for Organizational Behaviour Professionals |
| AOCA | Association For Ophthalmic Cooperation To Asia |
| AOCA | Automotive Oil Change Association |
| AOCE | Association of Oregon Corrections Employees |
| AOCM | Association Des Orphelins Chefs De Menages |
| AOCM | Association Of Ordinands And Candidates For Ministry |
| AODA | American Overseas Dietetic Association |
| AODC | Association Of Diving Contractors |
| AOFLA | Atlantic Offshore Fish and Lobster Association |
| AOLP | Association of Outdoor Lighting Professionals |
| AOPA | Aircraft Owners and Pilots Association |