| Abbreviation | Definition |
|---|---|
| ISRA | Iowa Street Rod Association |
| ITBS | Internet Tolkien Book Society |
| ITCH | International Team of Comics Historians |
| ITOG | Isuzu Troopers Owners Guild |
| IWCA | Iowa Wing Chun Association |
| IYCF | Improve Your Coarse Fishing |
| JAAP | Just All Amazing Puzzles |
| JAM | Japanese Anime and Manga |
| JAM | Jib And Main |
| JCSA | Jaguar Club of Southern Arizona |
| JCSN | Japan Crane and Stork Network |
| JCU | Jaguar Community United |
| JCV | Japan Club of Victoria |
| JDCN | Jaguar Drivers Club of Natal |
| JFR | Jewish Family Research |
| JFRG | Jewish Feminist Research Group |
| JFRG | Johns Family Research Group |
| JGL | Jewish Genealogy Links |
| JGO | Jewish Genealogy Organization |
| JGS | Jewish Genealogical Society |