| 584. Obed Calvaire | Drums | 1 |
| 584. Obed Vazques | Horns, Spoons | 1 |
| 584. Obi Nwadije | Percussion | 1 |
| 584. Obinna Enwere | Keys | 1 |
| 584. Odeal | Vocals | 1 |
| 584. Odessa Jorgensen | Violin | 1 |
| 584. Of Montreal | Featured Artist | 1 |
| 584. Ogueji Kenneth Uchenna | Guitar | 1 |
| 584. Oh Pep! | Featured Artist | 1 |
| 584. Ohmme | Featured Artist | 1 |
| 584. Okkervil River | Featured Artist | 1 |
| 584. Oklou | Guitar, Marimba, Piano, Recorder, Vocals | 1 |
| 584. Olabiyi Julius | Keys | 1 |
| 584. Old Crow Medicine Show | Featured Artist | 1 |
| 584. Ole Kirkeng | Bass | 1 |
| 584. Olena Tsybulska | Drums, Vocals | 1 |
| 584. Olga I. González | Background Vocals, Shaker, Tambourine | 1 |
| 584. Oli Harris | Cello | 1 |
| 584. Oli Jefferson | Drums | 1 |
| 584. Oli Langford | Violin | 1 |
| 584. Olive Hannah | Drums | 1 |
| 584. Oliver "Tuku" Mtukudzi | Featured Artist | 1 |
| 584. Oliver Bates Craven | Electric Guitar, Fiddle, Vocals | 1 |
| 584. Oliver Pinnell | Guitar | 1 |
| 584. Oliver Tuttle | Trombone | 1 |