| Orchestre symphonique de Québec | 0 | 0 |
| Orchestre symphonique de Sherbrooke | 1 | 0 |
| Orchestre symphonique de Trois‐Rivières | 0 | 0 |
| Orchestre symphonique de la RTBF | 5 | 0 |
| Orchestre symphonique d’Orléans | 0 | 0 |
| Orchestre symphonique et lyrique de Nancy | 0 | 0 |
| Orchestre à cordes du Festival de Paris | 0 | 0 |
| Ordeathral | 0 | 0 |
| Orden Ogan | 10 | 0 |
| Orecchiette | 0 | 0 |
| Oregon | 0 | 0 |
| Oregon Bach Festival Chamber Orchestra | 0 | 0 |
| Oregon Bach Festival Choir | 4 | 0 |
| Oregon Bach Festival Chorus | 0 | 0 |
| Oregon Bach Festival Orchestra | 4 | 0 |
| Oregon Ballet Theatre Orchestra | 0 | 0 |
| Oregon Repertory Singers | 0 | 0 |
| Oregon String Quartet | 0 | 0 |
| Oregon Symphony | 9 | 0 |
| Orem | 0 | 0 |
| Oren Gradus | 0 | 0 |
| Oren Marshall | 0 | 0 |
| Oren Shevlin | 1 | 0 |
| Orfeo 55 | 0 | 0 |
| Orfeo Orchestra | 21 | 0 |
| Orfeus Barock Stockholm | 0 | 0 |
| Orfeó Català | 4 | 0 |
| Orfeón Donostiarra | 19 | 0 |
| Orfeón Pamplonés | 1 | 0 |
| Orffit | 5 | 0 |
| Orford String Quartet | 0 | 0 |
| Organs Obsolete | 0 | 0 |
| Ori Kam | 2 | 0 |
| Ori Zur | 0 | 0 |
| Oria | 0 | 0 |
| Oriana Concert Choir | 0 | 0 |
| Oriana Concert Orchestra | 0 | 0 |
| Original Broadway Cast of Head Over Heels | 0 | 0 |
| Original New Orleans Ragtime Band | 0 | 0 |
| Origins | 3 | 0 |
| Oriol Martorell | 0 | 0 |
| Orion String Quartet | 0 | 0 |
| Orion Trio | 0 | 0 |
| Orion Weiss | 14 | 0 |
| Orjazztra Vienna | 0 | 0 |
| Orkest de Volharding | 2 | 0 |
| Orkest der Lage Landen | 0 | 0 |
| Orkester Nord | 4 | 0 |
| Orkiestra Akademii Beethovenowskiej | 0 | 0 |
| Orkiestra Filharmonii Rzeszowskiej | 0 | 0 |
| Orkiestra Filharmonii im. Henryka Wieniawskiego w Lublinie | 0 | 0 |
| Orkiestra Historyczna | 0 | 0 |
| Orkiestra Kameralna Filharmonii Narodowej | 7 | 0 |
| Orkiestra Opery na Zamku w Szczecinie | 0 | 0 |
| Orkiestra Polskiego Radia w Krakowie | 4 | 0 |
| Orkiestra Symfoniczna Akademii Muzycznej w Krakowie | 0 | 0 |
| Orkiestra Symfoniczna Filharmonii Narodowej | 86 | 0 |
| Orkiestra Symfoniczna Filharmonii Śląskiej | 16 | 0 |
| Orkiestra Symfoniczna Opery i Filharmonii Podlaskiej | 0 | 0 |
| Orkiestra Teatru Wielkiego w Warszawie | 0 | 0 |
| Orko Eloheim | 0 | 0 |
| Orla Rae | 0 | 0 |
| Orlanda Velez Isidro | 0 | 0 |
| Orlande de Lassus | 92 | 0 |
| Orlando | 0 | 0 |
| Orlando Allen | 0 | 0 |
| Orlando Bass | 3 | 0 |
| Orlando Consort | 38 | 0 |
| Orlando Gibbons | 43 | 0 |
| Orlando Jopling | 1 | 0 |
| Orlando Le Fleming | 0 | 0 |
| Orlando Philharmonic Orchestra | 0 | 0 |
| Orlando Pops Orchestra | 8 | 0 |
| Orlando String Quartet | 13 | 0 |
| Orlando Voorn | 8 | 0 |
| Orlando di Lasso Ensemble | 5 | 0 |
| Orlege | 0 | 0 |
| Orli Shaham | 11 | 0 |
| Orlin Anastassov | 1 | 0 |
| Orlok the Warlock | 0 | 0 |
| Ormandy | 0 | 0 |
| Ormond College Choir | 0 | 0 |
| Ormsby Wilkins | 0 | 0 |
| Ornamente 99 | 0 | 0 |
| Ornella Pulitó Santoliquido | 0 | 0 |
| Ornella Vanoni | 0 | 0 |
| Ornu | 0 | 0 |
| Orpharion Ensemble | 1 | 0 |
| Orphax | 0 | 0 |
| Orphei Drängar | 11 | 0 |
| Orphelion | 0 | 0 |
| Orpheon Consort | 2 | 0 |
| Orpheus 21 | 0 | 0 |
| Orpheus Chamber Orchestra | 76 | 0 |
| Orpheus Ensemble Berlin | 0 | 0 |
| Orpheus String Quartet | 0 | 0 |
| Orpheus Vokalensemble | 3 | 0 |
| Orphy Robinson | 0 | 0 |
| Orquesta Barroca de Sevilla | 0 | 0 |
| Orquesta Barroca de la Universidad de Salamanca | 0 | 0 |