- O
- OO
- OO
- OO
- OOak
- OakOb
- ObObl
- OblOC
- OCoce
- oceOct
- OctOcz
- OczOdd
- OddOdi
- OdiOed
- OedOff
- OffOff
- OffOGR
- OgrOh
- OhOhn
- OhnOje
- OjeOKA
- OKAOku
- OkuOla
- OlaOld
- OldOle
- OleOli
- OliOli
- OliOls
- OlsOma
- OmaOME
- OmeOmn
- OmnONA
- One
- OneOne
- Oneone
- oneONI
- OniOnl
- OnlOny
- OnyOoz
- OozOpe
- OpeOps
- OpsOra
- OraOrb
- OrbOrc
- OrcOrd
- OrdOrg
- OrgOri
- OriOri
- OriOrn
- OrnOrq
- OrqOrs
- OrsOrv
- OrvOsb
- Osbosh
- OshOsm
- OsmOsu
- OsuOth
- OthOtt
- Ott
- Our
- OurOut
- OutOut
- OutOuv
- OuvOve
- OveOvi
- OviOwe
- OweOxf
- OxfOza
- OzaOzu
- Ozuozz
- Opskamatrists, The
- Opsomer, Barbara (Belgian singer)
- Opstad, Jon
- Opti-Pop
- Optic
- optic core (experimental electronic/dance producer)
- Optic Nerve, The (80s NY garage rock band)
- Optic Sink
- Óptimo (bachata group/artist)
- Optimus (US rapper, aka Jordy Towers)
- Optimus Rhyme (US nerdcore hip hop group)
- Optiv & BTK
- Optiv & BTK feat. Ryme Tyme
- Optometry (John Tejada & March Adstrum)
- Opuntia (solo project of Mexico City producer Camila de Laborde)
- Opus (Austrian band; track: “Live Is Life”)
- Opus & Ambros, Wolfgang
- Opus & S.T.S.
- Opus 4 (French gipsy swing quartet)
- Opus 78
- Opus Alfa
- Opus Atlantica
- Opus Cuatro
- Opus Däi
- Opus featuring Buchebner, Erich, Schiffkowitz and Timischl, Günter
- Opus featuring Falco
- Opus featuring Gruber, Peter Niklas
- Opus featuring Kolonovits, Christian
- Opus featuring Musenbichler, Robby
- Opus III (English techno and house music)
- Opus III (Swedish trio)
- Opus Kink
- Opus Orange
- Opus Pro
- Opus X (Finnish classical ensemble)
- Opus X (Scandinavian pop)
- Opus.
- OQuadro
- Oquendo, Manny y Libre
- Oquendo, Manny's Libre
- Oques Grasses
- Oques Grasses & Doble
- Oques Grasses & Payés, Rita
- Oques Grasses & Santa Salut
- Oques Grasses & Stay Homas
- Oques Grasses, Al·lèrgiques al pol·len
- Oques Grasses, Figa Flawas
- Oques Grasses, Julieta
- OQueStrada
- OR (rap duo)
- Or Bleu
- Or Bleu featuring Lary Kidd
- Or du Commun, L’ (Belgian hiphop)
- Or du Commun, L’ feat. Elvis, Roméo
- Or du Commun, L’ feat. Elvis, Roméo, Caballero, Zwangere Guy
- Or du Commun, L’ feat. Lous and the Yakuza
- Or Noir (French TV show)
- Or, Rotem
- Or, Rotem
- Or, The Whale
- OR3O (fandom music producer/vocalist)
- OR3O & The Musical Ghost
- OR3O feat. Plexsy & Silva Hound
- Ora (Andrew Chalk & Darren Tate)
- Ora (late 1960s UK psychedelia)
- ORA (classical choir)
- ORA (Danish duo)
- Ora Mate
- Ora the Molecule
- Ora, Rita
- Ora, Rita feat. Brown, Chris
- Ora, Rita feat. Cardi B, Rexha, Bebe & Charli xcx
- Ora, Rita feat. Cole, J.
- Ora, Rita feat. Fatboy Slim
- Ora, Rita feat. Michaels, Julia
- Ora, Rita feat. Tempah, Tinie
- Ora, Rita feat. will.i.am
- Ora, Rita x Guetta, David x Imanbek
- Ora, Rita x Guetta, David x Imanbek feat. Gunna
- Ora, Rita x Imanbek feat. Khea
- Orachi, Alec
- Oracle (Indonesian Thrash Metal band)
- Oracle (Heavy Metal band from Gibraltar)
- ORACLE & Fractures
- ORACLE & Holochrome
- Oracle Hands (German Sludge/Post-Metal band)
- Oracle Sisters (Band from Paris, France)
- Oracles (indie psychedelic rock band from Berlin)
- Oraculum (US Progressive Metal/Shred band)
- Orage, L (from Italy)
