| Okean Elzy | Electronic musicRockSoundtrack | 5 |
| Owl City | PopRockChurch music | 3 |
| One Direction | Dance musicPop | 6 |
| Papin Olympos | RockPop RockAlternative rockIndependent musicPop | 6 |
| Don Omar | Dance musicPop | 2 |
| Ottawan | DiscoPop | 8 |
| Turlough O'Carolan | Classic | 6 |
| Sunn O))) | Rock | 1 |
| YK Osiris | Rap | 1 |
| Oasis | RockAlternative rockBalladHard rock | 8 |
| Octavian | Pop | 1 |
| Birds of Tokyo | Alternative rock | 1 |
