- O
- OO
- OO
- OOak
- OakObe
- ObeObs
- ObsOce
- OceOCT
- OctOda
- OdaODE
- ODEODU
- ODUOfe
- OfeOG
- OGOh
- OhOhl
- OhlOjo
- OjoOke
- okgOla
- OlaOld
- OldOle
- OleOli
- OliOlm
- OMA
- OmaOme
- OMEOMO
- OmoOnd
- OndOne
- OneONE
- OneOni
- OniOnr
- OnrOop
- OorOpe
- OpeOpu
- OpuOra
- OraOrc
- orcOre
- Ore
- OriORI
- OriOrn
- OrnOrq
- Orqort
- OrtOsb
- OsbOsi
- OsiOst
- OstOth
- OthOtt
- OttOum
- OunOut
- OutOut
- OutOv
- Ovove
- OveOwe
- OweOxa
- Oxb
- OzeOZZ
- Onra feat. B, Reggie
- Onrust (Dutch 2000s black metal)
- Onrust (Belgian post-metal band)
- Onsa Media (a group of musicians, who records covers mainly and sometimes original songs and parodies also)
- Onsind (acoustic pop punk band)
- Onslaught (UK punk/thrash/speed metal band)
- Onslow (Alternative rock band)
- Ontaneda, Sara
- ontologics
- Ontuak
- Onuabuobi, Victor (Nigerian gospel singer)
- Onuka
- Onuki, Taeko
- Onukwulu, Ndidi
- Onuma, Parsley
- onumi
- Onur Bostancı (Alternative, Pop)
- Onural, Cengiz
- Onurr
- Onward (US band)
- Onward to Olympas
- Onward, etc.
- Onyanko Club
- Onyeabor, Charles
- Onyeabor, William
- Onyioha, Oby
- Onyria (Oniria)
- Onysus
- ONYVAA
- Onyx (New York hardcore rap group)
- Onyx (Israeli psytrance artist/DJ Yanniv Gold Farb)
- Onyx (IDM artist, track "Under Pressure")
- Onyx & Dope D.O.D.
- Onyx Collective
- Onyx feat. ASAP Ferg & Price, Sean
- Onyx feat. DMX
- Onyx feat. Dope D.O.D.
- Onyx feat. Genovese
- Onyx feat. Havoc
- Onyx feat. Makem Pay
- Onyx feat. Papoose & Cormega
- Onyx feat. Reks
- Onyx, PTX & Domestic
- Onze:20
- OOBE (Italian techno/house producer)
- OOBE (Polish Rock Band)
- Ooberfuse
- Ooberman
- Oobie (Tenaia Sanders)
- Oobik & the Pucks
- Oodaredevil (Yeat collaborator aka DareDevil)
- ooes
- oofoe
- Oohlas, The
- OOHYO
- ooi (German indie pop band)
- Ooi, Imee
- OOJA, Ms. (hiphop)
- Oojami
- Ookay
- Ookla the Mok (filk group)
- Ooklah the Moc
- Öökülm
- Oolacile
- oomiee
- Oomori, Kinuko (Japanese singer)
- Oomori, Seiko (Japanese pop/rock singer-songwriter)
- Oomph!
- Oomph! feat. Adel, den, Sharon
- Oomph! feat. Apocalyptica
- Oomph! feat. Hagen, Nina
- Oomph! feat. Harms, Chris
- Oomph! feat. Jandová, Marta
- Oomph! feat. L'ÂME IMMORTELLE
- Oomph! feat. L’Âme Immortelle
- Oompie Koerier
- Oona (Graphic artist born Oona Leganovic)
- Oona (Oona Garthwaite and Dave Tweedie)
- Oonagh (Senta-Sofia Delliponti)
- Oonagh feat. Björn
- Oonagh feat. Celtic Woman
- Oonagh feat. Fischer, Helene
- Oonagh feat. Safri Duo
- Oonagh feat. Santiano
- OoOo
- oOoOO (witch house/electronic producer)
- öOoOoOoOoOo
- Ooopopoiooo
- oop, anna
- Oopopi Symphony Orchestra
