- O
- OO
- OO
- OO
- OOak
- OakOb
- ObObl
- OblOC
- OCOce
- OCEOct
- OctOcu
- OcuOdd
- OddOdi
- OdiODZ
- OeOff
- OffOff
- Offogo
- ogoOh
- OhOHN
- OhnOje
- OjeOKA
- OKAOku
- OkuOla
- OlaOld
- OldOle
- OleOli
- OliOli
- OliOls
- Ols
- OmaOme
- OmeOmn
- OmnOna
- OnaOne
- OneONE
- Oneone
- OneONI
- OniOnl
- OnlOny
- OnyOos
- OosOpe
- OpeOpp
- OprORA
- OraOrb
- OrbOrc
- OrcOrd
- OrdOrg
- OrgOri
- OriOri
- OriOrm
- OrmOrq
- OrqOrs
- OrsOru
- Osb
- OsbOse
- OseOsm
- OsmOst
- OstOth
- OthOtt
- OttOtw
- OtyOur
- OurOut
- OutOut
- OutOut
- OutOve
- OveOvi
- OviOwe
- Oweox
- OxaOys
- OysOzr
- OZRozz
- Octane (Philadelphia hard rock band)
- Octane & DLR
- Octane & DLR feat. Marion
- Octappella (United States contemporary a cappella)
- Octarium
- Octava Dimesión, La (Colombian salsa group in the 1980s/90s)
- Octavarium
- Octave (Iranian Band)
- 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 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)
- Octeto Buenos Aires
- octi
- Octinomos
- OCTiV
- OCTiV feat. Celldweller
- Octo Octa
- October 31 (US Heavy Metal)
- October Burns Black
- October Country
- October Dogs
- October Drift
- October Ember
- October Ends
- October Fall (piano-fueled pop punk band)
- October Falls (Finnish atmospheric black metal)
- October File
- October Jimmy
- October Light
- October London
- October London & Ledisi
- October London feat. Snoop Dogg
- October Noir
- October People
- October Project
- October Rage
- October Sky
- October Tide
- October Tooth (Zachary Threlkeld)
- October, Jonny (NYC rapper)
- Octoberman (Canadian indie rock band)
- Octobre (rock band from Quebec)
- Octobre Rouge (French rap group)
- Ôctôctô
- OctoLab
- 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
- OCTPATH
- Octubre (spanish power-pop)
- Octubre Doce
- OCULA
- OCULA feat. Tailor
- Oculist, The
- Oculos (Death/Thrash Metal band from Turkey)
