| Acronym | Definition |
|---|
| OAP | Old Age Pensioner (chiefly UK) |
| OAP | One Act Play |
| OAP | Old Age Pension |
| OAP | Open Access Plan (managed care) |
| OAP | Off-Axis Parabola (geometry) |
| OAP | On Air Promotion (broadcasting) |
| OAP | Ontario Automobile Policy |
| OAP | Orbiting Astronomical Observatory |
| OAP | One Arts Plaza (Dallas, TX) |
| OAP | One-Step Approval Procedure |
| OAP | l'Oreal Paris |
| OAP | Over-the-Air Programming (computing) |
| OAP | Open Air Pub (Engineering Undergraduate Society; McGill University; Canada) |
| OAP | Old Age Players (gaming group) |
| OAP | Ontario Association of Pathologists |
| OAP | Ocean Assessment Program (US NOAA) |
| OAP | Old and Putrid |
| OAP | Offset Aimpoint |
| OAP | Orthogonal Arrays of Particles |
| OAP | One Arm Pull-up |
| OAP | Occupational Aptitude Patterns |
| OAP | Old Age Person |
| OAP | Organizational Assessment Package |
| OAP | Oceanic Automation Program |
| OAP | Old Age Playstationer |
| OAP | Oficina de Atención Permanente (Guatemala) |
| OAP | Operations Approval Panel |
| OAP | Orbit Average Power (spacecraft electric power systems) |
| OAP | Ordered Access Pairs |
| OAP | Ove Arup & Partners Ltd |
| OAP | Outline Acquisition Plan |
| OAP | Offshore Assembly Provisions |
| OAP | Over Age Premium (logistics/shipping) |
| OAP | Optically Activated Pigmented (coating systems) |
| OAP | On Account Payment |
| OAP | Observe, Anticipate and Plan (driving safety) |
| OAP | Old Age Partner |
| OAP | Older Adults Program (various locations) |