- O Eco da Montanha
- O Legado
- O Sebbo
- O Terno
- O'shea the Cloudy King
- O.S.H. Ode To Space Hassle
- OAG
- Oasis
- Oban
- Objective Unknown
- Oblivious
- Obscure Sorrows Project
- Ocelot
- October Noir
- Octoteta
- Odd-Rey
- Oddvar Torsheim
- Odeón
- Odin Irgel Rock
- Odyssey
- Oedipus
- Of Kings and Courage
- OFFICE
- Oh! Caraga
- Oh! Danger
- Ohio Express
- Ohm
- Ohrenfeindt
- OIM Appear
- Oja & Tunable Band
- OJM
- Okinawa
- Ol' Rockin' Ern
- Ola Skei
- Old Chevy
- Old Monk
- Old Smoke Tales
- OldRich at CUni
- OldSchoolBasterds
- Oliver & The Alchemists
- Oliver & The Twisters
- Oliver Ignatius
- Oliver Ignatius
- Oliver Southgate
- Olivier Despax et ses Gamblers
- Olly Oxen
- Olly Riva
- Oly
- Olympics
- Omar & The Howlers
- Omar D Menta
- Omar Damo
- Omar Dykes
- On My Arms
- On Stuff
- On the Road
- One Horse Band
- One Tusk
- One-Trick Pony
- Oneself
- Onkel Egil
- ONOFF Band
- Ooga Boogas
- Oohlala
- Opaline
- Open Road
- OpenGlobe
- Opossums
- Opschaakl'n
- Ora Labora
- Orange Joe
- Orango
- Organic Jams
- Orient
- Originalsgrunt
- Orion
- Orlando Alvarado
- Orleans
- Orlek
- Orlie & The Saints
- Orquestra e Coro Cid
- Orquestra Internacional Maravella
- Ortega Vel
- Os 5 Jotas
- Os Aaalucinantes
- Os Bargs
- Os Bartira
- Os Belmonts
- Os Diamantes Negros
- Os Haxixins
- Os Hobbies
- Os Inflamáveis
- Os Leviatãs
- Os Megatons
- Os Nitroglicerinas
- Os Noctambulos
- Os Reincidentes
- Os Tartaros
- Os Titulares do Ritmo
- Os Vips
- Osage
- OSB
- Oscar McLollie & His Honey Jumpers
- Oseas
- Oseph Rudd
- Oslobodioci
- Ossi Brüder
- Otakus Beat
- Otis Blackwell
- Otis Williams
- OTWO
- Out of Time
- Outra Face
- Outras Velharias
- Outrider
- Outside the Box
- Outsideinside
- Outsiders
- Outtake of Evil
- Ouzo Bazooka
- Overfuzz
- OVERSMURF
- Overtone
- OVVN