| Oomp Camp |
| Oompa Loompa Cast |
| Oomph! |
| Oonagh |
| Op:l Bastards |
| OP8 |
| Opal |
| Opal Blue |
| Opal Josephs |
| Opal Onyx |
| Opalo y Negros |
| Open Arms |
| Open Form Trio |
| Open Hand |
| Open Mic Karaoke |
| Open Mike Eagle |
| Open Road |
| Openside |
| Opera |
| Opera Alaska |
| Opera Chaotique |
| Opera IX |
| Opera Magna |
| Opera Steve |
| Opera Trance |
| Operación Triunfo 2017 |
| Operación Triunfo 2018 |
| Operación Triunfo 2020 |
| Operacion Triunfo III |
| Operation Code 671 |
| Operation Ivy |
| Operator |
| Operator Please |
| Operators |
| Opetaia Foa'i |
| Opeth |
| Opgeblazen |
| Opgezwolle |
| Ophelia Pastrana |
| Ophelie Winter |
| Ophthalamia |
| Opi The Hit Machine |
| Opia |
| Opiate For The Masses |
| Opick |
| Opie |
| Opie Bellas |
| Opio |
| Opium Dream Estate |
| Opium G |
| Opium Jukebox |
| Opium Warlords |
| OPlus |
| Oplus Band |
| Opm |
| Opoloh |
| Opor Praput |
| Oppenheimer |
| Oppera |
| Oppie Andaresta |
| Opposite |
| Opposite Day |
| Opposite the Other |
| Oppressor |
| Opshop |
| Opt the Game Hustler |
| Optiganally Yours |
| Optik Crew |
| Optiloop |
| Optimo |
| Optimystic |
| Opus |
| Opus 3 Jazz Trio |
| Opus Cuatro |
| Opus III |
| Opus Mc |
| Opus Orange |
| Opus Pro |
| Opus47 |
| Opvs |
| Opwekking |
| Opwekking Crew |
| OQJAV |
| OQuadro |
| Oques Grasses |
| Oquestrada |
| Oquinto |
| Or |
| OR |
| Or-N-More |
| Ora |
| Oracle |
| Oracle Ball |
| Oral Majority |
| Oran "Hot Lips" Page & His Band |
| Oran "Juice" Jones |
| Oran Thaddeus Page |
| Orang Malaya |
| Orange |
| Orange 9mm |
