| Nouns | 4 | 1 |
| Nova Collective | 1 | 1 |
| Noveller | 2 | 1 |
| Novelli | 1 | 1 |
| November Ultra | 1 | 1 |
| Novi fosili | 1 | 1 |
| Novo Amor | 0 | 1 |
| Now, Now | 1 | 1 |
| Nsuase Kete Group | 0 | 1 |
| Nu Genea | 4 | 1 |
| Nuclear Assault | 1 | 1 |
| Nyctophiliac | 1 | 1 |
| O Yuki Conjugate | 1 | 1 |
| O. | 1 | 1 |
| O.A.R. | 12 | 1 |
| O.V. Wright | 10 | 1 |
| ODZ | 1 | 1 |
| OMI | 1 | 1 |
| ONI | 1 | 1 |
| OOIOO | 9 | 1 |
| OORUTAICHI | 0 | 1 |
| Oberon | 1 | 1 |
| Obie Trice | 1 | 1 |
| Obrad Milić | 1 | 1 |
| Obywatel G.C. | 1 | 1 |
| Oceansize | 4 | 1 |
| Octavio Corvalán | 1 | 1 |
| Octopus Diver | 0 | 1 |
| Odie Leigh | 0 | 1 |
| Offa Rex | 1 | 1 |
| Offset | 5 | 1 |
| Oh No | 21 | 1 |
| Oh, Rose | 1 | 1 |
| Ohio State University Marching Band | 1 | 1 |
| Oil Tasters | 0 | 1 |
| Oil on Canvas | 1 | 1 |
| Oiseaux-Tempête | 1 | 1 |
| Okay Kaya | 7 | 1 |
| Okay Temiz | 4 | 1 |
| Ola Gjeilo | 13 | 1 |
| Old 97’s | 15 | 1 |
| Old Saw | 1 | 1 |
| Oleś Brothers | 0 | 1 |
| Olga Mysłowska | 1 | 1 |
| Oliver | 1 | 1 |
| Olivia Jean | 1 | 1 |
| Ol’ Dirty Bastard | 5 | 1 |
| Omar LinX | 0 | 1 |
| Omen | 7 | 1 |
| Omerta | 0 | 1 |
| Omit | 1 | 1 |
| On Broken Wings | 1 | 1 |
| On the Might of Princes | 1 | 1 |
| One Direction | 5 | 1 |
| One Leg One Eye | 1 | 1 |
| One St. Stephen | 1 | 1 |
| Oneida | 22 | 1 |
| Ongoma | 1 | 1 |
| Oni Ayhun | 0 | 1 |
| Opal | 1 | 1 |
| Opening Performance Orchestra | 18 | 1 |
| Operating Theatre | 1 | 1 |
| Operation Cleansweep | 1 | 1 |
| Ophelia | 1 | 1 |
| Opus | 1 | 1 |
| Orange Goblin | 1 | 1 |
| Orchestra Njervudarov | 1 | 1 |
| Orchestra Super Mazembe | 1 | 1 |
| Orchestra of the Royal Opera House, Covent Garden | 83 | 1 |
| Orchestre National de Jazz | 1 | 1 |
| Orchestre Veve | 1 | 1 |
| Orchestre de l’Opéra de Lyon | 45 | 1 |
| Orchestre symphonique de Montréal | 108 | 1 |
| Oren Ambarchi | 1 | 1 |
| Oriental Sunshine | 1 | 1 |
| Orkestar Miće Nikolića | 1 | 1 |
| Orkestra Rumpilezz | 1 | 1 |
| Orkiestra Ósmego Dnia | 1 | 1 |
| Orla Gartland | 1 | 1 |
| Orlando Julius | 1 | 1 |
| Orphan | 0 | 1 |
| Orphan Boy | 3 | 1 |
| Orphaned Land | 1 | 1 |
| Orq. de Joseíto Fernández | 0 | 1 |
| Orquesta Cubana de Música Moderna | 1 | 1 |
| Orquestra Afrosinfônica | 1 | 1 |
| Orquestra de Cadaqués | 5 | 1 |
| Os Tincoãs | 1 | 1 |
| Os Tubarões | 4 | 1 |
| Osama | 1 | 1 |
| Osiris | 1 | 1 |
| Osjan | 1 | 1 |
| Oskorri | 1 | 1 |
| Ossian | 1 | 1 |
| Ostraca | 1 | 1 |
| Otep | 1 | 1 |
| Otomo Yoshihide’s New Jazz Ensemble | 1 | 1 |
| Otto Benson | 5 | 1 |
| Ought | 1 | 1 |
| Oumou Sangaré | 1 | 1 |