- O
- OO
- OO
- OO
- OO
- OOak
- OakObe
- ObeOBL
- OblObs
- Obsoce
- OceOce
- oceOct
- OctOda
- OdbOdd
- OddOde
- OdeODU
- ODUOf
- OfOff
- OFFOfi
- Ofiogo
- OGROh
- OhOhi
- OhiOIL
- OilOk
- OkOke
- OkeOl
- OlOla
- OlaOld
- OldOl
- OlOlg
- OlgOli
- OliOli
- OliOls
- OlsOMA
- OmaOma
- OmaOme
- OmeOmn
- OmnOn
- OnOne
- ONEOne
- OneOne
- OneOne
- OneONJ
- OnkOnn
- ONOOny
- OnyOos
- OosOpe
- OpOpi
- OpiOpu
- OpuOra
- Oraorb
- OrbOrc
- OrcOrc
- OrcOre
- OreOrh
- OrhOri
- ORIOrk
- OrkOrn
- OrnOrq
- OrqOrr
- OrrOrt
- OrtOsa
- OsaOsc
- OscOsk
- OskOss
- OssOT
- OtaOth
- OthOtt
- OttOtt
- OttOur
- OurOut
- OutOut
- OutOut
- OutOv
- OvOve
- OveOve
- OveOwe
- OweOwl
- OwlOxl
- Oxl
- OzaOzo
- OzoOzz
- Octavian Winters
- OCTAVIO
- Octavio Garcia
- Octavio Mai (French electronic/alternative duo of Juliette Bazenet and Johan Putet)
- Octavio the Dweeb
- Octavus Lupus (Symphonic metal band from Lieusaint, Île-de-France)
- octi
- Octinomos (Swedish black metal)
- OCTiV
- OCTiV feat. Celldweller
- Octo Octa
- October
- October 31 (US Heavy Metal)
- October Burns Black
- October Changes (Belgian gothic metal band)
- October Country
- October Dogs
- October Drift
- October Ember
- October Ends
- October Ends & Nick Thurl Mavromatis
- October Fall (piano-fueled pop punk band)
- October Falls (Finnish atmospheric black metal)
- October File
- October Game, The (UK alt rock band)
- October Jimmy
- October Light
- October London
- October London & Ledisi
- October London feat. Snoop Dogg
- October Noir
- October People
- October Project
- October Rage
- October Rising
- October Sky
- October Tide
- October Tooth (Zachary Threlkeld)
- October, Benedict
- October, Jonny (NYC rapper)
- Octoberman (Canadian indie rock band)
- Octoblien
- Octobre (rock band from Quebec)
- Octobre Rouge (French rap group)
- Ôctôctô
- OctoLab
- Octopie (Progressive rock band from Finland)
- Octoploid
- Octoploid feat. Joutsen, Tomi
- Octoploid feat. Koivusaari, Tomi
- Octoploid feat. Kotamäki, Mikko
- Octopus (UK britpop group)
- Octopus (1970s German progressive rock group)
- Octopus (1970s Belgian pop band)
- Octopus (Progressive metal band from Chile)
- Octopus (1970s British psychedelic pop band)
- Octopus (1970s UK psychedelic rock band from Hatfield)
- Octopus Montage
- Octopus Project, The
- Octopvs to the Party
- OCTPATH
- Octubre (spanish power-pop)
- Octubre Doce
- OCULA
- OCULA feat. LaRue, Phillip
- OCULA feat. Tailor
- Oculist, The
- Oculos (Death/Thrash Metal band from Turkey)
- Ocultan
- Ocults
- Oczojebny, Jakub
- Oczojebny, Jakub feat. Gwiazdunia, Temresa
- Oczojebny, Jakub feat. Kiti
- OD Band
- OD Bongo
- OD Kokemus
- Oda (Norwegian pop singer)
- Oda (French stoner doom band)
- Oda Loves You
- Oda, Hiroyuki pres. HanasoumenP
- Oda, Kaori (KAORI for Yuki Kajiura)
- Oda, Kazumasa
- Oda, Tetsurou
- Oda, Yuji
- Oda, Yuji
- ODAE
- Odal, Billy
- Odani, Misako
- Odar (Bosnian Black Metal from Sarajevo)
- Odawas
