| Abbreviation | Definition |
|---|---|
| ISST | International Schools Sports Tournament |
| ISST | International Schools Sports Tournaments |
| ISU | International Skating Union |
| ISWA | Indiana State Wrestling Association |
| IT | Indoor Track |
| ITA | Intercollegiate Tennis Association |
| ITA | International Taekwondo Association |
| ITBA | Irish Tenpin Bowling Association |
| ITC | International Tennis Centre |
| ITD | Inspirational Throw Down |
| ITF | International Taekwondo Federation |
| ITF | International Tennis Federation |
| ITFL | Internet Tecmo Football League |
| ITN | International Tennis Number |
| ITO | International Technical Official |
| ITPL | International Tennis Premier League |
| ITRO | Ice Training Review Organization |
| ITSF | International Table Soccer Federation |
| ITT | Intermediate Team Time |
| ITU | International Triathlon Union |