| Abbreviation | Definition |
|---|---|
| JGA | Junior Golf Association |
| JGC | Junior Global Cup |
| JGM | Junior General Meeting |
| JGT | Junior Golf Tour |
| JH | Junior Hunter |
| JHMG | Jackson Hole Mountain Guides |
| JIB | Jock In the Box |
| JIJ | Jazz in June |
| JJ | Jumping Jack |
| JJ | Jungle Jim |
| JJGF | Jiu Jitsu Global Federation |
| JJN | Ju Jitsu Norge |
| JJP | Jaw Joint Protector |
| JJR | J. J. Redick |
| JJSS | Jinmukan Japanese Sword School |
| JJV | Jamestown Junior Varsity |
| JKA | Japan Karate Association |
| JKD | Jeet Kune Do |
| JKF | Japan KARATE-DO Federation |
| JKI | Jikishin-Kai International |