| Abbreviation | Definition |
|---|---|
| ISEA | Inter-Society for the Electronic Arts |
| ISEE | International Social Enterprise Exchange |
| ISEO | International Sustainable Energy Organisation |
| ISEQ | Institute of Soil and Environmental Quality |
| ISES | Institute of Sport and Exercise Science |
| ISES | International Society of Exposure Science |
| ISES | International Solar Energy Society |
| ISESCO | Islamic Educational, Scientific and Cultural Organization |
| ISF | Ingénierie Sans Frontières |
| ISFP | International Society for Fibrinolysis and Proteolysis |
| ISFS | International Scholars and Faculty Services |
| ISGB | International Society of Glass Beadmakers |
| ISHK | Institute for the Study of Human Knowledge |
| ISHR | International Society for Heart Research |
| ISI | Information Society Index |
| ISI | Institute for Scientific Information |
| ISIPS | International Sharps Injury Prevention Society |
| IslamIFC | Islamic International Foundation of Cooperation |
| ISLT | International Snow Leopard Trust |
| ISMA | Internet Streaming Media Alliance |