- O
- OO
- OO
- OOak
- OakObe
- ObeObs
- ObsOce
- OceOct
- OctOdd
- OddODE
- ODEOdy
- OdyOff
- OffOG
- OGOh
- OhOHR
- OhrOk
- OkOkl
- OkmOla
- OlaOld
- OldOli
- OliOli
- OliOls
- OlsOma
- OmaOmi
- OmiOn
- OnOne
- OneOne
- OneOne
- OneOnl
- OnlOny
- OnyOpe
- OpeOPM
- OPMOra
- OraOrb
- OrbOrc
- OrcOrg
- OrgOri
- OriOrl
- OrlOrp
- OrpOrt
- OrtOsa
- OsaOsc
- OscOsm
- OsnOTE
- OTEOts
- Ots
- Ous
- OutOut
- OutOut
- OutOve
- OveOvn
- OvnOwl
- OwlOys
- OysOZw
- OZZ
- Omini
- Omino (Argentinian electronic rock)
- Ominous (Swedish melodic death/thrash metal band)
- Ominous (0minous)
- Ominous Eclipse (Canadian melodic death/thrash metal)
- Ominous Glory (USA power metal)
- Ominous Ruin (USA technical brutal death metal)
- Ominum
- Omission (Dutch hardcore band, active 2003 - 2007)
- Omit (melodic doom metal band based in Oslo, Norway)
- Omkara (New Age musician/singer/songwriter Lauren Piazza)
- Omloop, Laura (Belgian teen-pop singer)
- Omme Kolsoum
- Ommm (French vocal quintet group)
- Omnerod (Belgian progressive death metal)
- Omni (Los Angeles rapper J. McDonald)
- Omni (French pop/rock)
- Omni (US lo-fi pop band from Atlanta)
- Omni Gardens
- Omni Selassi (Swiss experimental rock)
- Omni Trio (drum and bass musician)
- Omnia (Neoceltic/Paganfolk)
- Omnia (trance producer Evgeny Smirnov)
- Omnia & Gallagher, Audrey
- Omnia & Ira
- Omnia feat. Burns, Christian
- Omnia feat. Loretta, Melissa
- Omnia feat. Nadeau, Danyka
- Omnia feat. Rose, Jonny
- Omnia feat. Wrigsell, Tilde
- omniboi
- omniboi feat. Fantasyluv
- omniboi feat. Zeph
- Omnific, The
- Omnific, The ft. Gober, Clay
- Omnihility
- Omnikrom
- Omnikrom ft. TTC
- Omnimar
- Omnimotion
- Omnioid
- Omnis (ambient / drone)
- Omnisoul
- Omnispawn
- Omnitica
- Omnitron (Thrash Metal band from Sweden)
- Omnium Gatherum
- Omnivide
- Omnivortex
- OMNOM (Tech House artist)
- Omnyama, Mfaz'
- Omodaka
- Omodaka (Soichi Terada)
- OMOH (Pop electro french duo)
- Omoinotake
- Omonoko (Northern Irish Alt pop quartet)
- OMORI (Composers of the video game soundtrack “Omori”)
- Omori, Cullen
- Omori, Hinako
- Ōmori, Toshiyuki
- Omosumo
- Omotola
- OMP
- Omp El Capitán (Dominican Christian music singer)
- OMR (French Rapper)
- Omri (emo electro)
- Oms, Kuba (Canadian soul singer and producer)
- Omul cu Șobolani
- Omulu + King Dou Dou
- OMY, The
- ON (Sylvain Chauveau and Steven Hess with rotating guest artists)
- ON (solo project of Ken Andrews)
- ON (Hardcore)
- on a créé un monstre
- On a Dead Machine
- On a Friday (pre‐Radiohead group, until 1991)
- On a Hiding to Nothing
- ON AN ON
- On Atlas’ Shoulders
- On Being an Angel
- On Being Human
- On Broken Wings
- On Call Heroes
- On Camera
- On Dead Waves
- On Holiday (Oklahoma City ska punk)
- On Inc.
- On My Honor
- On Planets & Flaws
- On Solid Ground
