- O
- OO
- OO
- OO
- OO
- OOak
- OakObe
- Obl
- OblObs
- ObsOce
- OceOch
- OchOct
- OctOdd
- OddOdd
- OddOde
- OdeODU
- ODUof
- OfOff
- OFFofi
- OFKOgr
- OGROh
- OhOhj
- OHKOin
- OIOOK
- OKOke
- OkfOl
- OlOla
- OlaOld
- OldOle
- OleOlh
- OlhOli
- OliOli
- OliOls
- OlsOma
- OmaOma
- OmaOme
- OmeOmn
- OmnOn
- OnOne
- OneOne
- OneOne
- Oneone
- OneOnk
- OnkOno
- OnoOny
- OnyOos
- OosOp
- OpeOpi
- OpiOpu
- OpuOra
- OraOrb
- OrbOrc
- OrcOrd
- OrdOre
- OreOrh
- OriOri
- OriOrk
- ORKOro
- OroOrq
- OrqOrr
- OrrOrt
- OrtOsa
- Osa
- OscOSK
- OskOss
- Oss
- OtaOth
- OthOtt
- OttOtt
- OttOur
- OurOut
- OutOut
- OutOut
- OutOv
- OvOve
- OveOve
- OveOwe
- OweOwl
- OwlOxm
- OxmOza
- OzaOzo
- OzoOzz
- Omnium Gatherum
- Omnivalent (Houston, TX Rock/Alt-Rock band)
- Omniversum fractum
- Omnivide (Canadian technical death metal)
- Omnivortex
- Omnizure
- OMNOM (Tech House artist)
- Omnya, Purge, The, Adjuzt, Griever & PL4Y feat. RXBY
- Omnyama, Mfaz'
- Omodaka
- Omodaka (Soichi Terada)
- Omodaka
- OMOH (Pop electro french duo)
- Omoi (Sakurai & Kimura)
- Ómoia
- Omoinotake
- Omole, Faith
- Omonoko (Northern Irish Alt pop quartet)
- Omoregie, Allen (Nigerian Gospel singer)
- OMORI (Composers of the video game soundtrack “Omori”)
- Omori, Aki
- Omori, Cullen
- Omori, Hinako
- Ōmori, Toshiyuki
- Omosumo
- Omoto, Trevor
- Omoto, Trevor & UNDY
- Omotola
- OMP
- Omp El Capitán (Dominican Christian music singer)
- OMR (Paris-based French Rapper)
- Omraz (Bulgarian Extreme Metal Band)
- Omri (emo electro)
- Oms, Kuba (Canadian soul singer and producer)
- Omul cu Șobolani
- Omulu & DUDA BEAT
- Omulu & Letrux
- Omulu & Maria Maud
- Omulu + King Doudou
- Omulu, DUDA BEAT & Lux & Tróia
- Omulu, Luna, Luedji & ÀTTØØXXÁ
- OMY, The
- OMYRA & Rubin, Josh
- ON (solo project of Ken Andrews)
- on a créé un monstre
- On a Dead Machine
- On a Hiding to Nothing
- ON AN ON
- On and Ons, The
- On Atlas’ Shoulders
- On Being an Angel
- On Being Human
- On Broken Wings
- On Camera
- On Dead Waves
- On File
- On Holiday (Oklahoma City ska punk)
- On Idyl
- On Inc.
- On Man
- On Man feat. Falola, Femi
- On My Command
- On My Honor
- On My Life
- On Piano (project created by Frank Iengo)
- On Planets
- On Planets & Blue Wednesday
- On Planets & Flaws
- On Planets & Hanz
- On Point Crew
- On Prend L'Air
- On Regret
- On Returning
- On Solid Ground
- On the Dot
- On the Floor (German gothic rock band from Hamburg)
- ON THE HUNT & Chandler
- 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 the Roof
- On Thorns I Lay (death/doom/gothic metal band from Greece)
- On Thorns I Lay (French Doom Metal Band)
- On Tonight
- On Video
- On Water (US metal band)
- On Wave (indie)
- On Your Feet, Original Broadway Cast of
