- O.D.2BlacK
- O.S.T
- October
- odd
- Official 髭男 dism
- Oikawa Mitsuhiro
- okadada
- Okasian
- Olde Worlde
- Once A Day
- onelifecrew
- Onigashima
- onoken
- Onose Masao Show
- Ordit
- ORESAMA
- Oriental Funk Stew
- ORIGINAL LOVE
- Original Taste
- Orijin
- Osamu Kitajima
- Osamu Miyaji
- Oskar
- otetsu
- Otokaze
- Outer
- OVER ARM THROW
- Owl Production
- OZ