| Acronym | Definition |
|---|
| IRG | Iranian Revolutionary Guard |
| IRG | International Resources Group |
| IRG | Independent Regulators Group (EU) |
| IRG | Informatics Research Group (various locations) |
| IRG | Immunology Research Group (University of Calgary) |
| IRG | International Research Group (various organizations) |
| IRG | Immunoreactive Glucagon |
| IRG | Insight Research Group (New York, NY) |
| IRG | Internal Research Grant (higher education) |
| IRG | Ghosthunters and the Incredibly Revolting Ghost |
| IRG | Iraqi Republican Guard |
| IRG | Interest Rate Guarantee |
| IRG | Internet Resource Guide |
| IRG | Inter Record Gap |
| IRG | Integrated Review Group |
| IRG | Initial Review Group |
| IRG | International Research Grant |
| IRG | Immediate Release Guidelines (World Customs Organization) |
| IRG | Inter-Record Gap |
| IRG | Interactive Research Group |
| IRG | International Rice Genebank |
| IRG | Imaging Research Group |
| IRG | Impôt Sur Le Revenu Global (French: Income Tax Global) |
| IRG | Insurance Research Group |
| IRG | Internationale des Résistants À La Guerre (French: War Resisters International) |
| IRG | Image Resource Group (Columbia, SC) |
| IRG | Infinity Resource Group (Berwyn, PA) |
| IRG | Insurance Rating Group |
| IRG | Innovative Resources Group, Inc. (Saratoga Springs, NY) |
| IRG | Incident Response Geographic Information System (California) |
| IRG | Idea Resource Group |
| IRG | Information Routing Group |
| IRG | Interagency Review Group on Nuclear Waste Management |
| IRG | Interdepartmental Regional Group |
| IRG | Inertial Rate Gyro |