- O
- OO
- OO
- OOas
- OatObl
- OblOce
- OceOck
- OckOda
- OdaODE
- ODEOes
- OetOff
- offO
- OGXOhi
- OhiOjo
- OjoOkl
- OklOlc
- OldOle
- OleOli
- OliOls
- OlsOma
- OmaOmn
- OmnOnc
- OncOne
- OneOne
- OneOnl
- OnlOOB
- OobOpe
- OpeOps
- OptOra
- OraOrc
- OrcORE
- OREOri
- OriOrl
- OrlOrq
- OrqOrw
- OrxOsc
- OscOsm
- OsmOte
- Oteott
- OttOui
- OuiOut
- OutOut
- OutOve
- OveOvi
- OviOwl
- OwlOys
- OysOZZ
- 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
- Onda (Michaelangelo L'Acqua & Gregg Fine)
- Onda Sabanera
- Onda Vaga
- Onda Vaselina
- Onda, Naoyuki
- Ondara, J.S.
- Ondatrópica
- Önder, Seda
- Onderadio
- Ondina (eurodance vocalist)
- Ondra, Jakub (Czech vocalist, guitarist and songwriter)
- Ondrasik, John
- Ondreaz
- Ondřej Havelka a jeho Melody Makers
- Ondskapt
- 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 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
- One Dimensional Man
- One Direction
- One Dollar Short
- One Dove
- ONE DRAFT
- One Drop (reggae group)
- 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
- One Flew West
- One for All (Jazz Group)
- One for the Team
- One for the Team (Indie Rock band from Minneapolis MN)
- One Hello World
- One Hit Wonder (California punk band)
- One Hope
- One Hundred Hours
- One Hundred, The
- One I Cinema
- One in a Million (1960s Scottish psychedelic band)
- One in a Million (Dutch rock/ska band)
- One Inch Punch (grunge/hip hop duo from Los Angeles)
- One King Down
- One Last Glance
- One Last Wish
- One Less Reason
