- O
- OO
- OO
- OO
- OOak
- OakOat
- OatObi
- ObiObs
- ObsOce
- OceOce
- OceOct
- OctOdd
- ODDOde
- OdeODO
- odoOes
- OesOff
- OffOff
- OffOgr
- OGROh
- OhOHN
- OHNOjb
- OjeOKA
- OKAokt
- OktOLA
- OlaOld
- OldOle
- OleOli
- OliOli
- OliOlm
- OlmOlv
- OlvOma
- OmaOme
- OmeOmo
- OmoOna
- ONBOne
- OneOne
- Oneone
- oneONG
- OngOnl
- OnlOnu
- OnuoOo
- Ope
- OpeOpi
- OpiOpu
- OpvOra
- OraOrb
- OrbOrc
- OrcOrd
- OrdOrg
- OrgOri
- OriOri
- Oriorm
- OrnOrp
- OrqOrr
- OrrOrt
- OrtOsb
- OsbOsc
- OscOsm
- OsmOst
- OstOTH
- OthOtr
- OtsOtt
- OttOur
- OurOut
- OutOut
- OutOut
- OutOve
- Oveove
- OveOVX
- OvyOwl
- OwlOxl
- OxlOzc
- OzcOzu
- Ozuozz
- 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 Below Joy (Charlotte, NC progressive rock)
- Once Blue
- Once Dead (Heavy Metal from L.A.)
- Once Grace Forever
- Once Human
- Once Human feat. Flynn, Robert
- Once Human, Flynn, Robert
- Once Monsters (UK Band)
- Once Monsters, Adams, Chloe
- Once Never Again (Belgian late 1990s hardcore band)
- Once Nothing
- Once Tasted Life
- Once Tiros
- Once Upon
- Once Upon a Dead Man
- Once Upon a Time (lead Bruno Adams)
- Once upon a winter
- Once, The
- Öncel, Nazan
- Öncel, Nazan & Manuş Baba
- OnCue
- Ond Cirkel
- Onda (Michaelangelo L'Acqua & Gregg Fine)
- ONDA ANDAR
- Onda Rossa Posse
- Onda Sabanera
- Onda Vaga
- Onda Vaga & Perotá Chingó
- Onda Vaga & Serrano, Jorge
- Onda Vaselina
- Onda, Carlo
- Onda, Naoyuki
- Ondagranda (italian duo, Dargen D'amico and Emliano Pepe)
- Ondara, J.S.
- Ondas Marteles, Las
- Ondatrópica
- Önder (Dutch-Turkish rapper Önder Doğan)
- Onderadio
- Onderkoffer
- Onderwater, Jeska
- Ondes Martenot, Les
- Ondina (eurodance vocalist)
- Ondolindë (Turkish Melodic Death Metal)
- 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)
- One (Canadian reggae group)
- One (UK rap crew, w/ members Sway, Pyrelli, etc.)
- 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 Big Game
- One Bit & Cyrus, Noah
- One Block Radius
- One Buck Short
- One Chance
- One Chance feat. Fabo
- ONE CHiN
- One Click Straight (Alternative Filipino Band)
- One Cool Guy
- One Culture
- One Culture & Mellodose
- One Dae
- One Day (Australian hip-hop)
