| OAPA | Of the American Planning Association 
| Others |
| OAPA | Offences Against the Person Act
| Others |
| OAPA | Office of Academic Planning and Accountability
| Others |
| OAPA | Office of Academic Planning and Assessment
| Others |
| OAPA | Office of Academic Program Assessment
| Others |
| OAPA | Office of Afghanistan and Pakistan Affairs
| Others |
| OAPA | Ohio Association of Physician Assistants
| Others |
| OAPA | Oklahoma Academy of Physician Assistants
| Others |
| OAPA | Oklahoma Asphalt Pavement Association
| Others |
| OAPA | Old Allentown Preservation Association
| Others |
| OAPA | Omaha Alumnae Panhellenic Association
| Others |
| OAPA | Only A Pavement Away
| Others |
| OAPA | Ontario Association of Psychological Associates
| Others |
| OAPA | Opacity associated protein A
| Others |
| OAPA | Open Access Prepaid Account
| Others |