| Abbreviation | Definition |
|---|---|
| JKM | Jan Knippenberg Memorial race |
| JKO | Japan Karate-do Organization |
| JKR | Japan Karate-do Ryobu-kai |
| JLA | Joe Louis Arena, Detroit, Michigan |
| JLAA | Junior League of Ann Arbor |
| JLB | Junior League Baseball |
| JLC | Junior Lifeguarding Club |
| JM | Junior Midget |
| JMAA | Jabari's Martial Arts Academy |
| JMD | Jai Mata Di |
| JMW | Junior Middleweight |
| JO | Japan Open |
| JO | Jeux Olympiques |
| JO | Junior Olympics |
| JOAD | Junior Olympic Archery Development |
| JOC | Japanese Olympic Committee |
| JOSC | Junior Olympic Shotgun Camp |
| JOX | Jocks |
| JP | Jab Punch |
| JP | Jump Power |