| Abbreviation | Definition |
|---|---|
| IRS | Société Internationale Renardienne |
| IRS | Socit Internationale Renardienne |
| IRSA | Interventional Radiology Society of Australasia |
| IRSA | Irish Research Scientists' Association |
| IRSK | International Relations Society of Kenya |
| IRSS | International Rough Set Society |
| IRSSA | Industrial Relations Society of South Australia |
| IRTS | Imperial Russian Technical Society |
| IRTS | Imperial Russian Technological Society |
| IRTS | International Radio and Television Society |
| IRTS | Irish Radio Transmitters Society |
| IS | Informal Settler |
| ISA | Asociacin Internacional de Sociologa |
| ISA | Asociación Internacional de Sociología |
| ISA | Association Internationale de Sociologie |
| ISA | Indian Society of Anaesthesiologists |
| ISA | Institution of Surveyors, Australia |
| ISA | International Society of |
| ISA | International Society of Andrology |
| ISA | International Society of Audiology |