- O
- OO
- OO
- OOak
- OakObe
- ObeObs
- ObsOce
- Oceoch
- OchOct
- OctOde
- OdeOdo
- OdoOfa
- OfaOff
- OffO
- OOha
- OhaOiz
- OizOKA
- OKAOl
- OlOld
- OldOle
- OleOli
- OliOli
- OliOls
- OlsOma
- OmaOml
- OmmOn
- OnOne
- OneOne
- OneOne
- OneOnl
- OnlOny
- OnyOpe
- OpeOpi
- OpiOra
- OraOrb
- OrbOrc
- OrcOre
- OreOri
- OriOrk
- OrkOro
- OrpOrr
- OrrOrw
- OrwOsb
- OsbOsk
- OskOst
- OstOth
- OthOtt
- OttOur
- OurOut
- OutOut
- OutOva
- OvaOve
- OveOwe
- OweOxb
- Oxe
- OzeOZZ
- Obscenity Trial
- Obscura (technical death metal band from Munich, Germany)
- Obscura Qalma (Symphonic death metal from Venice, Italy)
- Obscura Religio
- Obscurcis Romancia
- Obscure (Bangladeshi band)
- Obscure Anachronism
- Obscure Disorder
- Obscure Sphinx
- Obscure, The
- Obscurity (Swedish death metal band)
- Obscurity (Black/Viking metal band from Germany)
- Obsequiae
- Observatory, The (US rock band from Athens, Georgia)
- Observatory, The (Singaporian space rock)
- Observe & Control
- Observer (Shoegaze)
- Observer Drift
- Obsessed, The (doom metal music)
- Obsession (UK dance remakes for Almighty Records)
- Obsession (American metal)
- Obsessive (1990s techno/trance artist David Lübner)
- Obsessives, The
- Obsidia (Dubstep/Dubstyle/Drum & Bass/Electronic Producer from the UK)
- Obsidia & Boyinaband
- Obsidian Kingdom
- Obsidian Mind
- Obsidian Shell
- Obsidian Shrine
- Obsidian Tide
- Obsidian Tongue (US atmospheric black metal)
- Obsidiots
- Obsidious
- Obskür (Dublin duo)
- Obskür (Obskür)
- Obsolescence
- Obsolete Humanity (Belgian death/groove metal band)
- Obsolete Theory
- Obsoletos
- Obstetra (Grindcore from Spain)
- Obstrukt
- OBSYDIA (NIJISANJI EN VTuber group)
- Obtained Enslavement
- Obtest
- Obukuro, Nariaki
- Obús
- obylx
- Obywatel G.C.
- OC Hermo
- OC Saint
- OC Ska Kids
- OC Times (Barbershop Quartet)
- OC, Charlotte (Singer)
- Ocak, Arif Erdem
- Ocaklı, Erkan
- Öçal, Burhan & Trakya All Stars, The
- Ocampo, Pablo
- Ocaña, Chico
- Ocarina
- Ocasek, Ric
- Ocaso (Hardcore deathcore band from Chile)
- Occams Laser
- Occas (new age)
- Occasional Dreams
- Occasionally Humans
- Occasionally, Jordan
- Occidens
- Occult Hand Order
- Occultation (US Doom Metal)
- Occults
- Occurrence (Experimental Electronic Pop Band from NYC)
- OCD (Philadelphia rap duo)
- Oceaán (Brussels-born Manchurian electronic music producer)
- Oceán (Czech electronic group)
- Ocean (1970s Canadian gospel/soft rock band)
- Ocean (Swiss soft rock/folk rock band)
- Ocean (Polish rock band)
- Ocean Alley
- Ocean Blue, The (American indie pop)
- Ocean Chief
- Ocean Colour Scene
- Ocean Drive
- Ocean Drive feat. Oriska, DJ
- Ocean Flaws
- Ocean Floor (Northern UK alt-rock 4 piece)
- Ocean Grove (Australian nu metal band)
- Ocean Grove (United States)
- Ocean Grove feat. Adult Art Club & New Babylon
- Ocean Grove feat. Dune Rats
- Ocean Grove feat. lil aaron
