- O
- OO
- OO
- OO
- OOAF
- OAFOak
- OakObe
- ObeObo
- OboOca
- OcaOce
- OceOct
- OctOct
- Octodd
- OddODE
- ODEOdo
- OdrOf
- OfOff
- OFFOfi
- OFKOgr
- OgrOh
- OhOhn
- OhnOJ
- OJOKA
- OkaOko
- OkoOla
- OlaOld
- Oldold
- OldOle
- OleOli
- OliOli
- OliOls
- OlsOMA
- OmaOMB
- OMBOmi
- OmiOMP
- OmpOnc
- OncOne
- OneOne
- Oneone
- oneONG
- OngOnl
- OnlOnu
- OnuOon
- OonOpe
- OpeOph
- OphOpu
- OpuOra
- OraOrb
- OrbOrc
- OrcOrd
- OrdOre
- OreOri
- OriOri
- OriOrl
- OrlOro
- OroOrq
- OrqOrt
- OrtOry
- oryOsb
- OsbOsh
- OshOsm
- OsmOST
- OSTOth
- OthOts
- OtsOtt
- OttOur
- OurOut
- OutOut
- OutOut
- OutOv
- OvOve
- OveOvi
- OviOwe
- OweOx
- OXOYM
- Oyo
- ozz
- Oonagh (Senta-Sofia Delliponti)
- Oonagh & Santiano
- Oonagh feat. Björn
- Oonagh feat. Celtic Woman
- Oonagh feat. Fischer, Helene
- Oonagh feat. Safri Duo
- Oonagh feat. Santiano
- OoOo
- oOoOO (witch house/electronic producer)
- öOoOoOoOoOo
- Ooopopoiooo
- oop, anna
- Oopopi Symphony Orchestra
- Oopsy (Rapper)
- Oorah (Orthodox Jewish Outreach Organization)
- Oordaya (aka Clara Guenot)
- Oorka
- Oort, Bart van (pianist)
- Oôs Joôs (West-Frisian rock & roll group, performing songs in dialect)
- Öösorr
- Oosten, Michael
- Oosterhuis, Huub
- Oosterhuis, Trijntje
- Oosterhuis, Trijntje & Amuedo, Leonardo
- Oosterhuis, Trijntje & Jazz Orchestra of the Concertgebouw
- Oosterhuis, Trijntje & Metropole Orkest
- Oosterhuis, Trijntje feat. Clayton–Hamilton Jazz Orchestra, The
- Oosterhuis, Trijntje feat. Clayton–Hamilton Jazz Orchestra, The
- Oosterhuis, Trijntje feat. Clayton–Hamilton Jazz Orchestra, The and McComb, Frank
- Oosterhuis, Trijntje feat. Dulfer, Candy
- Oosterhuis, Trijntje met McComb, Frank
- Oosterhuis, Trijntje met Richie, Lionel
- Oot n' Oots, The
- Ootam (French rapper)
- Ootsuki, Maki
- Ooyy (Henrik Olsson, Swedish composer and producer)
- Ooyy & HDBeenDope
- Ooze (Swedish ambient producer Sebastian Mullaert)
- Ooze, Ivan
- Oozes, The
- Oozora, Subaru
- OP8 (Giant Sand/Lisa Germano collaboration)
- OP8 feat. Germano, Lisa
- Opa Cupa
- Opa! (Colombian band)
- Opaal (Munich Pop duo)
- Opaali
- Opac (French psych-folk band from Tours (One-man project : Pierre-Alexis Cottereau, but performing in band))
- Opal (80s US alternative rock band)
- Opal In Sky
- Opal Onyx
- Opalo
- Opał (Polish MC)
- Opał & Gibbs
- Opambuo International Band of Ghana
- Opania, Marian
- Opanije
- Opaque (gypsy swing from Peterborough, UK)
- Opatovský, Robo
- Opbrouck, Wim (Belgian actor & musician)
- Opća opasnost
- OPcrotte
- Opé Smith (France)
- Opeia, Cazzi
- Opel, Billy
- Opel, Jackie
- Open
- Open Access (Polish power folk metal band)
- Open Air Stereo
- OPEN ARMS (UK Pop Band)
- Open Boundaries & Lazerpunk
- Open Circle, The (Belgian dub techno producer)
- Open City (Punk Hardcore)
- Open Fifth
- Open Hand (American indie rock band)
- Open House (Celtic folk band)
- Open Kids
- Open Letter, An
- Open Mike Eagle (US rapper and comedian)
- Open Mike Eagle & White, Paul
- Open Mike Eagle feat. Alpha MC
- Open Mike Eagle feat. Buress, Hannibal
- Open Mike Eagle feat. Ferreira, R.A.P., Still Rift and Video Dave
- Open Mike Eagle feat. Has‐Lo
- Open Mike Eagle feat. Kool A.D.
- Open Mike Eagle feat. Nocando & Barman, Paul, MC
- Open Mike Eagle feat. Serengeti
- Open Mike Eagle feat. Toy Light
- Open Mike Eagle feat. Video Dave and Still Rift
- Open Mike Eagle feat.Brown, Danny
