| Acronym | Definition |
|---|
| IRSO➣Institute of Road Safety Officers (UK) |
| IRSO➣Institut de recherche en santé d’Ottawa (French: Ottawa Health Research Institute, Ottawa, Canada) |
| IRSO➣Islamic Resistance Support Organization (Hezbollah charity fund) |
| IRSO➣Iranian Society of Ophthalmology (est. 1947) |
| IRSO➣Installation Radiation Safety Officer |
| IRSO➣International Road Safety Organization |