- Original Rockers
- Octagon Man
- Old Joe Clarks
- Other Side
- Oscar Rabin
- O.G. Style
- Olivelawn
- Orso
- Ophelias
- On Borrowed Time
- Oscar G y su Grupo Sol
- Opium Taylor
- Orthotonics
- Officer Negative
- One Dead Three Wounded
- Olivier Manchon
- Orquesta Estrellas Cubanas
- O.B. Buchana
- Omid
- Obi Best
- Otway & Barrett
- Ottopasuuna
- Os Rosales
- Owusu & Hannibal
- Otto Waalkes
- Orquesta La Moderna Tradicion
- Of Mexican Descent
- Open City
- Orquesta Aliamen
- Orouni
- One Family
- Otis Ball
- Oasis Praise
- Overdrive Amp Explosion
- O.E.
- Operation Re-Information
- One'sy Mack
- Orpheum Bell
- Odair Assad
- Olivia Block
- Orquesta Flamboyan
- Onalaska
- Orphan Train
- Orlando Collado
- Original Piano Trio
- Orchestra Marrabenta Star De Mocambique
- Overstep
- Orison
- Opsvik & Jennings
- One of the Loudest Tragedies Ever Heard...
- Opaz
- Off The International Radar
- Orphan Allies
- One 4 One
- Oswego
- Oscar Noriega
- Oskay & O'Domhnail
- One Eighty
- Orangeburg Massacre
- Opaque
- Outrun the Gun
- Orange Colored Sky
- One True Voice
- One Umbrella
- O Positive
- Octillian
- Olli Dittrich
- Owen Bradley
- On Dout Kout Chenn
- Origin Of Species
- Ohio National Baptist Mass Choir
- Orphaned to Hatred
- Opram
- Organizacion Genesis
- Orquestra Os Jovens Do Prenda
- O.M.U.
- OC
- Ourselves Among Others
- Orion's Gate
- Ode for Joe
- One Orphan More
- Orange Risdon
- Orquesta del Desierto
- Olmir Stocker
- Our American Cousins
- Ome Henk
- Owal
- Odd Børretzen & Lars Martin Myhre
- Oliver Kalkofe
- One Riot One Ranger