| OIA | Old Ignatian Association | 旧伊格纳蒂亚协会 |
| OIA | Oceanic Industries Association | 海洋工业协会 |
| OIA | Outdoor Industry Association | 户外行业协会 |
| OIA | Oakland International Academy | 奥克兰国际学院 |
| OIA | Orlando International Airport, Orlando, Florida USA | 奥兰多国际机场，美国佛罗里达州奥兰多 |
| OIA | Oficina de InformaciÓn del Arzobispado | Oficina de InformaciÓn del Arzobispado |
| OIA | Ontario Institute of Agrologists | 安大略省农学研究所 |
| OIA | Office of Insular Affairs | 岛屿事务办公室 |
| OIA | Overseas Investment Act | 《海外投资法》 |
| OIA | Optional Inventory Adjustment | 可选库存调整 |
| OIA | Office of International Activities (EPA) | 国际活动办公室（EPA） |
| OIA | Office of the Assistant Secretary for Information Analysis | 信息分析助理秘书长办公室 |
| OIA | Order of Independent Americans | 独立美国人勋章 |
| OIA | Oregonians in Action | 俄勒冈人在行动 |
| OIA | Operational Impact Assessment (military rating of the impact of testing failures) | 作战影响评估（测试失败影响的军事评级） |
| OIA | Office of Internal Audit (government) | 内部审计办公室（政府） |
| OIA | Office of Integrative Activities | 综合活动办公室 |
| OIA | Office of International Affairs | 国际事务办公室 |
| OIA | Office of Internal Affairs | 内政部办公室 |
| OIA | Office of Indian Affairs | 印度事务办公室 |
| OIA | OrganizaciÓn Israelita Argentina (Peronist Jewish organization in the late 1940s and early 1950s) | OrganizaciÓn Israelita Argentina (Peronist Jewish organization in the late 1940s and early 1950s) |
| OIA | Old Indo-Aryan (linguistics) | 古印度-雅利安语（语言学） |
| OIA | Office of Instructional Assistance | 教学援助办公室 |
| OIA | Office of Imagery Analysis (CIA) | 图像分析办公室（CIA） |
| OIA | Outerworld Investigation Agency (gaming, Mortal Kombat Special Forces Organization) | 户外调查局 |