| Abbreviation | Definition |
|---|---|
| ILOC | International Laverda Owners Club |
| ILR | International Llama Registry |
| IMHA | International Miniature Horse Association (Namibia) |
| IMLF | International Miniature Llama Federation |
| INCC | International Nippon Collectors Club |
| INK | International Network for Knitters |
| INU | Inter Networkers United |
| IOT | Illuminates Of Thanateros |
| IPBA | International Perfume Bottle Association |
| IPKA | Irish Power Kite Association |
| IPMS | International Plastic Modeler's Society |
| IPPA | Indo-Pacific Prehistory Association |
| IRA | I Ran-over your Aunt |
| IRFCA | Indian Railways Fan Club |
| ISBA | Illinois State Beekeepers Association |
| ISBG | Isles of Scilly Bird Groups |
| ISCA | International Show Car Association |
| ISCA | International Show Caves Association |
| ISMCS | International Sewing Machine Collectors' Society |
| ISRA | International Star Riders Association |