- O
- OO
- OO
- OO
- OOak
- OakOat
- OatObi
- ObiObs
- ObsOce
- OceOce
- OceOct
- OctOdd
- OddOde
- OdeODM
- OdmOer
- OerOff
- OffOff
- Offogo
- OGROh
- OhOhm
- OHMOja
- OjaOka
- OkaOkt
- OktOla
- OLAOld
- OldOle
- OleOli
- OliOli
- OliOll
- OllOLU
- OluOm
- OmOme
- OmeOmo
- OMOOna
- OOne
- OneOne
- OneOne
- oneOne
- ONFOnl
- Onl
- Oon
- OonOpe
- OpeOpi
- OpiOpu
- OpuOra
- OraOrb
- OrbOrc
- OrcOrd
- OrdOrg
- OrgOri
- OriOri
- OriOrm
- OrmOrp
- OrpOrr
- OrrOrt
- OrtOsb
- OsbOsc
- OscOsl
- Osl
- OstOte
- OTFOtr
- OTROtt
- OttOur
- ourOut
- OutOut
- OutOut
- OutOVE
- OVEove
- OveOVS
- OvtOWI
- OwiOxl
- OxlOzc
- OzcOzu
- Ozuozz
- Obscure, The
- Obscurest Vinyl (parody music)
- 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)
- Observer (Shoegaze)
- Observer Drift
- Obsesion, La (La Obsesión Factory)
- Obsessed, The (doom metal music)
- Obsession (UK dance remakes for Almighty Records)
- Obsession (New Haven, CT metal)
- Obsessive (1990s techno/trance artist David Lübner)
- Obsessives, The
- Obsidia (Dubstep/Dubstyle/Drum & Bass/Electronic Producer from the UK)
- Obsidian Kingdom
- Obsidian Mantra (Polish Prog Death Metal)
- Obsidian Mind
- Obsidian Shell
- Obsidian Shrine
- Obsidian Tide
- Obsidian Tide feat. LePond, Michael
- Obsidian Tide feat.LePond, Michael
- Obsidian Tongue (US atmospheric black metal)
- Obsidian Voice
- Obsidiots
- Obsidious
- Obskür (Dublin duo)
- Obskür (Obskür)
- Obskuros
- Obsolescence
- Obsolete Humanity (Belgian death/groove metal band)
- Obsolete Theory
- Obsoletos
- Obstetra (Grindcore from Spain)
- Obstler
- Obstrukt
- Obstruktor
- OBSYDIA (NIJISANJI EN VTuber group)
- Obtained Enslavement
- Obtest
- Obukuro, Nariaki
- Obús
- Obviously
- obylx
- Obywatel G.C.
- OBZ (Dutch Group)
- OC Chris
- OC Hermo
- OC Saint
- OC Ska Kids
- OC Times (Barbershop Quartet)
- OC Tolbert
- OC, Charlotte (Singer)
- Ocak, Arif Erdem
- Ocaklı, Erkan
- Öçal, Burhan
- Öçal, Burhan & Trakya All Stars, The
- Ocampo, Pablo
- Ocaña, Chico
- Ocarina
- Ocasek, Ric
- Ocaso (Hardcore deathcore band from Chile)
- OCB (alias of Moroccan DJ & producer Driss Bennis)
- Ocboyblau
- Occams Laser
- Occas (new age)
- Occasional Dreams
- Occasionally Humans
- Occasionally, Jordan
- Occidens
- Occult Hand Order
- Occultation (US Doom Metal)
- Occults
- Occultus (Occultus Melodic Black Metal band from Cali Colombia)
- 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 (1960s US folk rock band)
- Ocean Alley
- Ocean Beats & Shiloh Dynasty
- Ocean Between Us, An
- Ocean Between Us, The
- Ocean Blue, The (American indie pop)
- Ocean Chief
