- O
- OO
- OO
- OO
- OOaf
- OAFOaK
- OakOBE
- ObeObn
- OBO
- Oce
- OceOCS
- OCTOct
- OctOdd
- OddODE
- ODEOdo
- OdoOf
- OfOff
- OffOff
- OfiOgr
- Ogroh
- OhOHN
- OHNOiz
- OizOka
- OKAOkl
- OklOla
- OlaOld
- OldOld
- OldOle
- OleOli
- OliOli
- OliOls
- OlsOm
- OmOma
- OmaOMG
- OMGOmo
- OmoOna
- OnaOne
- OneONE
- ONEOne
- ONEOne
- OneOnl
- OnlOns
- OnsOom
- OomOpe
- OpeOpg
- OpgOpt
- OptOra
- OraOrb
- OrbOrc
- OrcOrc
- orcOre
- OreOrh
- OrhOri
- ORIOrk
- ORKOro
- OroOrq
- OrqOrs
- OrsOrt
- OrtOsb
- OsbOsc
- OscOsl
- OslOst
- Ote
- OteOTR
- OTROtt
- OttOug
- OugOus
- OusOut
- OutOut
- OutOut
- OutOve
- OveOve
- OVEOwe
- OweOwl
- Owl
- Oxx
- Ozz
- Ozzozz
- 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 & 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 Honor
- On My Life
- 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 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
- On-lyne (Warframe fictional boy band)
- ON-OFF (AC/DC cover band from northern Italy)
- On-The-Go
- ON! (aka Tequila & the Sunrise Gang) (German punk-rock band)
- ON/OFF (Japanese Band)
- On/Off (Dutch techno duo)
- Ona
- Ona Mae
- Ona Nua
- Onabule, Ola
- ONAIR
- Önal, Ayşe Hatun
- Önal, Füsun
- Onar (Polish MC)
- Onar gościnnie Lerek
- Onarsé
- Onasis, Ariez
- Onasis, Ariez feat. Cossom, Kevin
