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