- O
- OO
- OO
- OO
- OO
- OOak
- OakObe
- ObeOBL
- OblObs
- Obsoce
- OceOce
- oceOct
- OctOda
- OdbOdd
- OddOde
- OdeODU
- ODUOf
- OfOff
- OFFOfi
- Ofiogo
- OGROh
- OhOhi
- OhiOIL
- OilOk
- OkOke
- OkeOl
- OlOla
- OlaOld
- OldOl
- OlOlg
- OlgOli
- OliOli
- OliOls
- OlsOMA
- OmaOma
- OmaOme
- OmeOmn
- OmnOn
- OnOne
- ONEOne
- OneOne
- OneOne
- OneONJ
- OnkOnn
- ONOOny
- OnyOos
- OosOpe
- OpOpi
- OpiOpu
- OpuOra
- Oraorb
- OrbOrc
- OrcOrc
- OrcOre
- OreOrh
- OrhOri
- ORIOrk
- OrkOrn
- OrnOrq
- OrqOrr
- OrrOrt
- OrtOsa
- OsaOsc
- OscOsk
- OskOss
- OssOT
- OtaOth
- OthOtt
- OttOtt
- OttOur
- OurOut
- OutOut
- OutOut
- OutOv
- OvOve
- OveOve
- OveOwe
- OweOwl
- OwlOxl
- Oxl
- OzaOzo
- OzoOzz
- Ottobrenero (Italian progressive metal)
- Ottolien (brother duo from Hanover)
- Ottolini, Mauro
- Ottolini, Mauro e la sua Orchestra Ottovolante
- Ottolini, Mauro, Sousaphonix
- Ottolini, Robyn
- Ottoman (Icelandic blues rock band)
- OttoMattic
- Ottone Pesante (Italian band)
- ottori (vocaloid producer)
- OTTTO
- OTTTO feat. Oliveri, Nick
- Ottum, Josh
- Otu (Finnish audio engineer & musician, Moonic Productions)
- Otuafi, Nela
- otuka
- Otur
- OTUS (Italian sludge/doom metal band)
- Ótvar Pestis (Hungarian rapper)
- Ótvar Pestis & Ricky the Tricky
- Otway, John
- Otway, John & Barrett, Wild Willy
- Otway, John & Barrett, Wild Willy
- otxhello
- Otyg
- Otyken (Siberian aborigine’s music group)
- Otzeki
- Ötzi (Oakland post-punk)
- Ötzi, DJ (Austrian entertainer and schlager singer)
- Ötzi, DJ & Bellamy Brothers, The
- Ötzi, DJ & Friedle, Lisa‐Marie
- Ötzi, DJ & Gott, Karel
- Ötzi, DJ & HBz
- Ötzi, DJ & Hermes House Band
- Ötzi, DJ & P., Nik
- Ötzi, DJ & P., Nik
- Ötzi, DJ & Stereoact
- Où est le Swimming Pool (English synthpop group)
- Ou, Wesley
- Ou2s (french rapper)
- Ouai Stéphane
- Ouaipaul
- Oualid (Dutch rapper/vocalist Oualid Roshdy)
- Oub LCK
- OUBEL
- Oubéret
- Oublaire
- Oubliette (melodic black metal band from Tennessee)
- Ouboter, Maaike
- Oud west
- Ouellet, Karim
- Ouellet, Karim feat. Sarahmée
- Ouellet, Yvan
- Ouertani, Abderraouf
- Ougenweide
- Ought (Canadian post-punk band)
- Oui 3
- Oui lele
- oui merci (Montreal indie rock band)
- Ouija (French progressive rock band)
- Ouija Macc
- Ouija Macc & E., Baby
- Ouijabeard (Rock, Hardrock, Metall)
- Ouimette, Steve
- Ouin, DJ
- Ouineta
- OuiOui
- Oulahlou
- Oulton, Quinn
- Oum (Oum el Ghaït Benessahraoui)
- Oum Shatt
- Oumar (French rapper Oumar Magassa)
- Oumua
- Ounsworth, Alec
- Oupa
- Our 11th Hour (Progressive Rock Group from Syracuse, NY)
- Our Anthem
- Our Broken Garden
- Our Ceasing Voice
- Our Ceasing Voice & Ryan, Matthew
- Our Common Collapse (Deathcore band from Minnesota)
- Our County Line (independent music project)
- Our Daily Bread
- Our Darkest Days
- Our Dementia Choir
- our distant worlds
- Our Fears
- Our Final Hour (US?)
- Our Final Hour (Isle of Man)
- Our First Brains
