| Abbreviation | Definition |
|---|---|
| IHI | Institute for Healthcare Improvement |
| IHPVA | International Human-Powered Vehicle Association |
| IHR | Institute for Historical Review |
| IHRA | International Human Rights Association |
| IHRI | International Human Rights Initiative |
| IHRLG | International Human Rights Law Group |
| IHRSA | International Health Racquet and Sportsclub Association |
| IHS | International Headache Society |
| IHS | International Health Service |
| IHS | International Herpetological Society |
| IHSOFMN | International Health Service of Minnesota |
| IHSPakistan | Integrated Health Services, Pakistan |
| IIB | Institute for Independent Business |
| IICL | Institute of International Container Lessors |
| IICR | Institute for Intellectual Capital Research |
| IIFAR | Incurably Ill For Animal Research |
| IIFC | Islamic International Foundation of Cooperation |
| IIGT | International Institute of Greater Toledo |
| IIHS | Insurance Institute for Highway Safety |
| IIIP | Institute for Information Infrastructure Protection |