- O
- OO
- OO
- OOak
- OakObe
- ObeObs
- ObsOce
- Oceoch
- OchOct
- OctOde
- OdeOdo
- OdoOfa
- OfaOff
- OffO
- OOha
- OhaOiz
- OizOKA
- OKAOl
- OlOld
- OldOle
- OleOli
- OliOli
- OliOls
- OlsOma
- OmaOml
- OmmOn
- OnOne
- OneOne
- OneOne
- OneOnl
- OnlOny
- OnyOpe
- OpeOpi
- OpiOra
- OraOrb
- OrbOrc
- OrcOre
- OreOri
- OriOrk
- OrkOro
- OrpOrr
- OrrOrw
- OrwOsb
- OsbOsk
- OskOst
- OstOth
- OthOtt
- OttOur
- OurOut
- OutOut
- OutOva
- OvaOve
- OveOwe
- OweOxb
- Oxe
- OzeOZZ
- 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
- Omnipotence (Canada / Death/Black Metal)
- 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 Man
- On My Honor
- On Planets & Flaws
- On Regret
- On Solid Ground
- On the Last Day
- On the Line All-Stars, The
- On the Loose (doom metal band from Portugal)
- On the Might of Princes
- On the Rocks (all male a cappella group from the University of Oregon)
- On Thorns I Lay (death/doom/gothic metal band from Greece)
- On Thorns I Lay (French Doom Metal Band)
- On Tonight
- On Video
