| Acronym | Definition |
|---|
| OAB | Ordem dos Advogados do Brasil (Brazil) |
| OAB | Offline Address Book |
| OAB | Oman Arab Bank |
| OAB | Oracle Advanced Benefits |
| OAB | Outlook Address Book |
| OAB | One to All Broadcast |
| OAB | Over-Active Bladder (urology) |
| OAB | Outlook Address Book (Microsoft) |
| OAB | Old Age Benefits |
| OAB | Old Administration Building (various locations) |
| OAB | Ofis Ar Brezhoneg (Breton: Breton Language Office; France) |
| OAB | Oita Asahi Broadcasting (Japan) |
| OAB | Ocean Affairs Board |
| OAB | Osan Air Base (Pyong-Taek City, Kyong-Gi Province, ROK) |
| OAB | Operations Approval Board (USAF) |
| OAB | Operational Archives Branch (US Navy; Washington, DC) |