| Acronym | Definition |
|---|
| RKK | Rooms Katholieke Kerk (Dutch: Roman Catholic Church) |
| RKK | Regionális Kutatások Központja (Hungarian: Center for Regional Studies) |
| RKK | Rissho Kosei-Kai (Buddhist movement) |
| RKK | Rummel, Klepper and Kahl, LLP (Richmond, VA) |
| RKK | Regionalverband Karnevalistischer Korporationen (Croatian: Regional Carnival Corporations) |
| RKK | Runda Kumpalan Kecil (Malay; Thai militant group) |
| RKK | Rahvusvaheline Kaitseuuringute Keskus (Estonian: International Center for Defence Studies; EU) |
| RKK | Ryukyu Kenpo Kata (martial art) |