| Acronym | Definition |
|---|
| OIA | Office of International Affairs |
| OIA | Outdoor Industry Association |
| OIA | Official Information Act (New Zealand Parliament) |
| OIA | Orlando International Airport |
| OIA | Oahu Interscholastic Association |
| OIA | Operator Information Area |
| OIA | Organización Internacional Agropecuaria (Spanish: International Agriculture Organization; Argentina) |
| OIA | Office of International Activities (EPA) |
| OIA | Oregonians in Action |
| OIA | Office of Internal Audit (government) |
| OIA | Office of Internal Affairs |
| OIA | Organización Indígena de Antioquía (Spanish: Indigenous Organization of Antioquia; Antioquia, Columbia) |
| OIA | Office of Indian Affairs |
| OIA | Old Indo-Aryan (linguistics) |
| OIA | Opportunity International Australia |
| OIA | Organización Israelita Argentina (Peronist Jewish organization in the late 1940s and early 1950s) |
| OIA | Office of Imagery Analysis (CIA) |
| OIA | Office of the Assistant Secretary for Information Analysis |
| OIA | Outerworld Investigation Agency (gaming, Mortal Kombat Special Forces Organization) |
| OIA | Office of Instructional Assistance |
| OIA | Operational Impact Assessment (military rating of the impact of testing failures) |
| OIA | Oceanic Industries Association |
| OIA | Old Ignatian Association |
| OIA | Order of Independent Americans |
| OIA | Organize It All (various organizations) |
| OIA | Organization of Independent Artists (New York) |