| Acronym | Definition |
|---|
| OPIR➣Overhead Persistent Infrared |
| OPIR➣Office of Planning and Institutional Research (various universities) |
| OPIR➣Office of Program and Integrity Reviews (Social Security) |
| OPIR➣Organization for the Promotion of International Relations (Japan) |
| OPIR➣Office of Pharmaceutical Industry Research (Japan; est. 1999) |