| Original West End Cast of Heathers |
| Original Wolverines |
| Originally Nowhere |
| Originetic |
| Originoo Gunn Clappaz |
| Origins |
| Orihuela M.S.S. |
| Oriole Terrace Orchestra |
| Orion |
| Orion Fellas |
| Orion Paxx |
| Orion's Room |
| Orion the Hunter |
| Orionjustmelted |
| Orions Belte |
| Orisa |
| Orishas |
| Oriste Femi |
| Orka Orkestrası |
| Orkan |
| Orkes A Hizadin |
| Orkesterpop |
| ORKID |
| Orkide |
| Orkidea |
| Orkiestra Opery w Warszawie |
| Orkiestra Polskiego Radia |
| Orkiestra Polskiego Radia Studio S1 |
| Orkiestra Reprezentacyjna Akademii Górniczo-Hutniczej |
| Orkiestra Symfoniczna Filharmonii Narodowej |
| Orkiestra symfoniczna Sinfonia Varsovia |
| Orkiestra taneczna |
| Orkiestra uliczna z Chmielnej |
| Orkiestra W. Dana |
| Orkiestra Wieniawa |
| Orkiestra Z Chmielnej |
| Orking |
| ORKN |
| Orkun Enver |
| Orkun Işıtmak |
| Orkundk |
| ORLA |
| Orla Gartland |
| Orlando |
| Orlando Brown |
| Orlando Contreras |
| Orlando Dixon |
| Orlando Gibbons |
| Orlando Julius |
| Orlando Liñan |
| Orlando Marconi |
| Orlando Morais |
| Orlando Murden |
| Orlando Philharmonic Orchestra |
| Orlando Pops Orchestra |
| Orlando Silva |
| ORLANN DIVO |
| Orleans |
| Orleya |
| Orloge Simard |
| Ormly Gumfudgin |
| Ormonde |
| Orna |
| Ornamento y Delito |
| Ornaree |
| Ornatos Violeta |
| Ornella Di Santis |
| Ornella Vanoni |
| Ornette |
| Ornette Coleman |
| Ornette Coleman Quartet |
| Ornette Coleman Quintet |
| Orni |
| Ornly You |
| Oro Bianco |
| Oro Ferreira |
| Oro Norteño |
| Orochen |
| Orochi |
| Orofino |
| Orondé |
| Orozco |
| Orpha |
| Orphan Twins |
| Orphanage |
| Orphaned Land |
| Orphanesta |
| Orphans |
| Orphans String and Brass Orchestra |
| Orphean Jet Sonic |
| Orphéon Célesta |
| Orpheus |
| Orpheus Kid |
| Orpine |
| Orquesta Akokan |
| Orquesta América |
| Orquesta Aragón |
| Orquesta Basura |
| Orquesta Bebo Olivieri Y Bob Sheridan |
| Orquesta Billo's Caracas' Boys |
