- O
- OO
- OO
- OOak
- OakObi
- ObiObs
- ObsOce
- OceOct
- OctOdd
- OddOde
- OdeOef
- OehOff
- OffOgd
- OgdOh
- OhOi
- OiOk
- okOku
- OkuOld
- OldOld
- OldOli
- OliOli
- OliOls
- OlsOMB
- OMBOmn
- OmnO
- OnaOne
- OneOne
- OneOng
- OngOno
- OnoOom
- OomOpe
- OpeOpt
- optOra
- OraOrc
- OrcOrd
- OrdOrh
- OrhOri
- OriOrm
- OrmOrq
- OrqOrt
- OrtOsb
- OsbOsi
- OsiOst
- OstOth
- OthOtt
- OttOur
- OurOut
- OutOut
- OutOve
- OveOve
- OveOwe
- OweOxl
- OxlOzm
- OZMOZZ
- Onay, Gülsin
- ONBC (Danish indie rock)
- Onbeskaamd (Afrikaans worship music project group based in South Africa)
- Once (Germany)
- Once a Pawn
- Once a Tree
- Once Again (Dancefloor project by Michael Schendel, active in the mid 1990s)
- Once and Future Band
- Once Blue
- Once Dead (Heavy Metal from L.A.)
- Once Human
- Once Human feat. Flynn, Robert
- Once Human, Flynn, Robert
- Once Monsters (UK Band)
- Once Never Again (Belgian late 1990s hardcore band)
- Once Nothing
- Once Tiros
- Once Upon a Dead Man
- Once Upon a Time (lead Bruno Adams)
- Once upon a winter
- Once, The
- Öncel, Nazan
- OnCue
- Ond Cirkel
- Onda (Michaelangelo L'Acqua & Gregg Fine)
- Onda Sabanera
- Onda Vaga
- Onda Vaselina
- Onda, Carlo
- Onda, Naoyuki
- Ondara, J.S.
- Ondas Marteles, Las
- Ondatrópica
- Önder (Dutch-Turkish rapper Önder Doğan)
- Onderadio
- Ondina (eurodance vocalist)
- Ondra, Jakub (Czech vocalist, guitarist and songwriter)
- Ondrasik, John
- Ondreaz
- Ondřej Havelka a jeho Melody Makers
- Ondskapt (Swedish black metal)
- Ondt Blod (Norwegian hardcore punk band)
- OnDubGround
- OnDubGround feat. Brother Culture
- One (Greek/Cypriot pop boyband)
- One (Florida hard rock band, affiliated with Sevendust)
- One (UK rap crew, w/ members Sway, Pyrelli, etc.)
- One (UK late 60s psychedelic rock band)
- ONE (South Korean rapper)
- One (80s UK band with Steve Hovington & Seven Webster)
- One 2 (US rapper)
- One 2 Many
- ONE 3rd NOTES
- One Acen
- One Acen feat. WSTRN
- One Adam 12
- One AM Radio, The
- One America (One America)
- One Bad Pig
- One Bad Son
- One Be Lo
- One Be Lo feat. Decompoze
- One Be Lo feat. Kadi
- One Bit & Cyrus, Noah
- One Block Radius
- One Buck Short
- One Chance
- One Chance feat. Fabo
- One Click Straight (Alternative Filipino Band)
- One Cool Guy
- One Day (Australian hip-hop)
- One Day Alive (Heavy Metal Band)
- One Day as a Lion
- One Day Hero
- One Day Remains (Based in Switzerland)
- One Dead Three Wounded
- One Desire (Melodic rock band from Finland)
- One Dimensional Creatures (Manchester, UK - alt punk/post-punk/grunge)
- One Dimensional Man
- One Direction (English‐Irish pop boy band)
- One Dollar Short
- One Dove
- ONE DRAFT
- One Drop (reggae group)
- One dying wish (Italian band)
- One eskimO
- One Eye Closed
- One Eyed Moon (garage/punk/stoner rock band from Atlanta, Georgia)
- One Fine Day (German rock/punk band)
- One Flew South
