| Abbreviation | Definition |
|---|---|
| ISQC | International Society of Qualified Coaches |
| ISR | International Society of Radiology |
| ISRA | Idaho Society of Radio Amateurs |
| ISRA | International Society for Research Activity |
| ISRB | International Society of Rider Biomechanics |
| ISRC | Illinois Society for Respiratory Care |
| ISRC | Indiana Society for Respiratory Care |
| ISRR | International Society of Root Research |
| ISRS | International Society for Reef Studies |
| ISRS | International Society of Refractive Surgeons |
| ISRT | Idaho Society of Radiologic Technologists |
| ISRT | Indiana Society of Radiologic Technologists |
| ISRT | Iowa Society of Radiologic Technologists |
| ISRTP | International Society of Regulatory Toxicology and Pharmacology |
| ISS | 'F,EF "E'1 'J1'F |
| ISS | International Superyacht Society |
| ISS | Iranian Statistical Society |
| ISS | Iron & Steel Society |
| ISS | Iron and Steel Society |
| ISSA | Islamic Society of Seacoast Area |