| Acronym | Definition |
|---|
| IRB | Internal Revenue Bulletin (Internal Revenue Service) |
| IRB | International Rugby Board |
| IRB | Institutional Review Board |
| IRB | Immigration and Refugee Board (Canadian immigration) |
| IRB | Internal Ratings Based (banking; risk management) |
| IRB | Institute for Research in Biomedicine |
| IRB | Internal Review Board |
| IRB | Industrial Revenue Bond |
| IRB | Integrated Routing and Bridging |
| IRB | Institut de Recherché en Biotechnologie (French) |
| IRB | Irish Republican Brotherhood |
| IRB | Indian Rocks Beach (Florida) |
| IRB | Independent Review Board |
| IRB | Investment Review Board |
| IRB | Industrial Robot |
| IRB | Interactive Ruby Shell (programming) |
| IRB | Industrial and Regional Benefits (Canada) |
| IRB | Inshore Rescue Boat |
| IRB | Industrial Regional Benefits |
| IRB | Individual Record(s) Brief |
| IRB | Improved Ribbon Bridge |
| IRB | Intel Research Berkeley (UC Berkeley) |
| IRB | Industrial Relations Board |
| IRB | International Register on Biosafety |
| IRB | Infrared Brazing |
| IRB | Indian Reserved Battalion |
| IRB | Independent Research Board |
| IRB | Income Replacement Benefit (Ontario Accident Benefits Schedule) |
| IRB | I Are Back |
| IRB | Internal Review Budget |
| IRB | Interruption Request Block |
| IRB | Incident Report Book (police) |
| IRB | Internet Renaissance Band |
| IRB | Industrial Relations Bulletin |
| IRB | Infrastructure Review Board |
| IRB | Initial Review Board |
| IRB | Inflatible Rescue Boat |
| IRB | Inspection Review Board |
| IRB | Inner Radiation Belt |
| IRB | Institutional Review Branch (various organizations) |
| IRB | Iron Rotating Band |
| IRB | Inspection Requirements Branch (US Navy) |
| IRB | Industrial Readjustment Branch |
| IRB | Instrumentation/Relay Board |
| IRB | Inducto-Ratio Bridge |
| IRB | Interest Buy-Down |
| IRB | Irregular Route Motor Carriers Bureau |
| IRB | Impulse Resistance Bridge |
| IRB | Improved Rotor Blade |
| IRB | Intelligence Review Board |
| IRB | Internationally Recognized Border |
| IRB | Irregular Billing |
| IRB | Institut Rudjer Boskovic (Croatian research institute) |