- O
- OO
- OO
- OO
- OO
- OOak
- OakObe
- ObeObl
- OblObs
- OBSOce
- OceOch
- OchOct
- OctOdd
- OddOde
- OdeOdi
- OdiOdy
- OdyOfe
- OfeOff
- OffOga
- OgaOh
- OhOha
- OhaOi
- OiOjo
- OjoOka
- OkaOku
- OkuOla
- OlaOld
- Oldold
- OldOle
- OleOli
- OliOli
- OLIOls
- OlsOM
- omOma
- OmaOme
- OmeOmn
- OmnOn
- OnOne
- OneOne
- OneOne
- OneOne
- OneONL
- ONLOno
- OnoOob
- OOcOP
- OpaOpe
- OpeOpp
- OppOr
- OrOra
- OraOrb
- OrbOrc
- OrcOrd
- OrdOrf
- OrfOri
- OriOri
- OriOrl
- OrlOro
- OroOrq
- OrqOrt
- OrtOrx
- OryOsb
- OsbOse
- OseOsm
- OsmOst
- OSTOte
- OteOto
- OtoOtt
- OttOu
- OuaOUR
- OurOut
- OutOut
- OutOut
- OutOve
- OveOve
- OveOvt
- OvvOwe
- OweOxh
- OxiOza
- OzaOzo
- OzoOZZ
- Omnium Gatherum
- Omnivalent (Houston, TX Rock/Alt-Rock band)
- Omnivide (Canadian technical death metal)
- Omnivortex
- 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)
- 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 (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 and Ons, The
- On Atlas’ Shoulders
- On Being an Angel
- On Being Human
- On Broken Wings
- On Camera
- On Dead Waves
- On Holiday (Oklahoma City ska punk)
- 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 Solid Ground
- On the Dot
- On the Floor (German gothic rock band from Hamburg)
- On the House
- 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 Rise
- 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 Trial
- On Video
- On Water (US metal band)
- On Wave (indie)
- On Your Feet, Original Broadway Cast of
