| Abbreviation | Definition |
|---|---|
| INANG | I Need A New Group |
| INCC | Ivanhoe Northcote Canoe Club |
| IOC | Inner Olympic Club |
| IOC | International Outdoor Club |
| IOCJ | infoScoop OpenSource Club Japan |
| IOCR | Intruder Owners Club România |
| IOCR | Intruder Owners Club Russia |
| IOMC | Indicator Of The Month Club |
| IOMC | Iron Order Motorcycle Club |
| IOTC | Indianapolis Obedience Training Club |
| IPC | International Polo Club |
| IPFSC | Ice in Paradise Figure Skating Club |
| IPFSC | Ice Palace Figure Skating Club |
| IPSC | International Private Society Club |
| IRC | Innova Riders Club |
| IRCA | International Radio Club of America |
| IRCA | International Real Combat Association |
| IRCC | Indian River Colony Club |
| IRCC | Indiana Radio Club Council |
| IRDC | International Race Drivers Club |