- O'Brien, Barry
- O'Brien, Tim
- O'Brien, Tim
- O'Connell, Maura
- O'Connor, Nora
- O'Connor, P.J.
- O'Connor, Sinead
- O'Jays, The
- O'Neal, Shaquille
- O'Neill, Matthew
- O'Riordan, Dolores
- Oasis
- Obenski, Amy
- Oberst, Conor
- Object
- Obnox
- Ocean Blue, The
- Ocean, Billy
- Ocean, Frank
- Ochs, Phil
- October Project
- Odds, The
- Odell, Tom
- Odonis Odonis
- Of Monsters And Men
- of Montreal
- Off Ramps, The
- Off With Their Heads
- Office Of Future Plans
- Offspring, The
- OGD
- Ogden, Shantell
- Oh Lonesome Ana
- ohGr
- Ohlman, Christine (Christine Ohlman & Rebel Montez)
- Ojeda, Amber
- OK Go
- Okkervil River
- Oksendal
- Okuté
- Old 97's
- Old Blind Dogs
- Old Firm Casuals, The
- Old No. 5's, The
- Oldfield, Mike
- Oldfield, Sally
- Oleander
- Olney, David
- Olnick, Joe
- Olson, Mark (Mark Olson & The Original Harmony Ridge Creekdippers)
- Omar And The Howlers
- Ombre
- Omhouse
- Omni
- Omni Gardens & Zen Monk Jogen
- Once & Future Band
- One Dove
- One High Five
- One Step Away
- OneRepublic
- Ong, Shueh-li
- Ono, Yoko
- Onore, Jeff
- Ontologics
- Ookla The Mok
- Open Head
- Open Window
- Opeth
- Opprobrium
- Orange 9mm
- Orange County Supertones
- Orange Goblin
- Orange Velvets, The
- Orange, The
- Oratory
- Orb, The
- Orbison, Roy
- Orbit Service
- Orcas
- Orchestral Manoeuvres In the Dark
- Orford, Martin
- Origami Ghosts
- Orions Belte
- Orqid
- Orton, Beth
- Osborne, Anders
- Osbourne, Ozzy
- Osbourne, Ozzy
- Oscher, Paul
- OSI
- Osmond, Donny
- Osmond, Donny & Marie
- Osmonds, The
- OSYX, The
- Other Lives
- Otis, Shuggie
- Otobo
- Oumbadougou, Abdallah
- Out Cold
- Outkast
- Over The Rhine
- Overkill
- Overloaded
- Owen
- Owsley
- Oxcart
- Oxys, The
- Oyunn
- Ozomatli
- Ozric Tentacles