- 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
- Ochs, Conny
- Ochs, Phil
- Ochunism
- Ocie Elliott
- Ócio (Brazilian rock band)
- Ock, Sam
- Ockeghem, Johannes (Franco-Flemish early Renaissance composer)
- Ockeroid
- Ockert, Darren
- Ockham’s Razor (folk rock quartet based out of Seattle)
- OCN
- OCnotes
- oco.
- Ocote Soul Sounds
- OCS
- OCS (dutch rapper)
- OCT
- Octafonic
- Octagon, Dr.
- Octagon, Dr. feat. Dexter
- Octahvia (US house/dance vocalist Octavia Lambertis)
- Octale (Belgian progressive metal band)
- Octane (Philadelphia hard rock band)
- Octane & DLR
- Octane & DLR feat. Marion
- Octarium
- Octava Dimesión, La (Colombian salsa group in the 1980s/90s)
- Octavarium
- Octave Cat
- Octave Lissner
- Octave Minds (Chilly Gonzales and Boys Noize collaboration)
- Octave Minds feat. Chance the Rapper & Social Experiment, The
- Octave Noire (formerly known as Oh Morice)
- Octave One (Burden brothers, US techno producers)
- Octave One feat. Saunderson, Ann
- Octaves (US hardcore band from Baltimore, MD)
- Octaves, Les
- Octavia (Bolivian pop)
- Octavia Sperati (Norse gothic metal band)
- Octavia Wakes
- Octavian (South-London based rapper)
- Octavian feat. ABRA
- Octavian feat. ASAP Ferg
- Octavian feat. J Rick & Ware, Jessie
- Octavian feat. London, Theophilus
- Octavian feat. Skepta & Phantom, Michael
- Octavian feat. Smokepurpp
- Octavian Ft. Future
- Octavian ft. Gunna & SAINt JHN
- Octavian ft. Phantom, Michael
- Octavian ft. Skepta
- Octavian Winters
- OCTAVIO
- 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
- OCTiV
- OCTiV feat. Celldweller
- Octo Octa
- October 31 (US Heavy Metal)
- October Burns Black
- October Country
- October Dogs
- October Drift
- October Ends
- October Fall (piano-fueled pop punk band)
- October Falls (Finnish atmospheric black metal)
- October File
- October Jimmy
- October Light
- October London
- October Noir
- October Project
- October Rage
- October Sky
- October Tide
- October Tooth (Zachary Threlkeld)
- Octobre (rock band from Quebec)
- Octobre Rouge (French rap group)
- Ôctôctô
- OctoLab
- 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
