- O
- OO
- OO
- OO
- OOak
- OakObe
- ObeObr
- OBSOcc
- OccOce
- OceOct
- OCTOdd
- OddODE
- ODEOdu
- ODUOfe
- OfeOFF
- offOgi
- OgiOh
- OhOhn
- OhnOji
- OjiOka
- OkaOku
- OkuOla
- OLAOld
- OldOle
- OleOli
- OliOli
- OllOls
- OlsOm
- OmOme
- OmeOmo
- OMOOnc
- OncOne
- OneOne
- OneOne
- OneONL
- ONLONR
- OnrOok
- Ope
- OpeOpi
- OpiOqu
- OquOra
- OraOrb
- ORBorc
- orcOre
- OreOri
- OriOri
- ORIOrl
- Orlorp
- OrpOrq
- OrrOrt
- OrtOsb
- OsbOsc
- OscOsm
- Osmost
- OstOth
- OthOtt
- OttOtw
- OtwOur
- OurOut
- OutOut
- OutOuu
- OuvOve
- OveOvi
- OviOwe
- OweOxi
- OxiOzc
- OzcOZw
- OZwozz
- Öökülm
- Oolacile
- Oolacile feat. Code: Pandorum
- oomiee
- Oomori, Kinuko (Japanese singer)
- Oomori, Seiko (Japanese pop/rock singer-songwriter)
- Oomph!
- Oomph! feat. Apocalyptica
- Oomph! feat. Hagen, Nina
- Oomph! feat. Harms, Chris
- Oomph! feat. Jandová, Marta
- Oomph! feat. Kieß, Stephanie
- Oomph! feat. L'ÂME IMMORTELLE
- Oomph! feat. L’Âme Immortelle
- Oomph! feat. Sharon den Adel
- Oona (Graphic artist born Oona Leganovic)
- Oona (Oona Garthwaite and Dave Tweedie)
- 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
- Oosterhuis, Trijntje
- Oosterhuis, Trijntje & Amuedo, Leonardo
- 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 Kraayenhof, Carel en Jansen, Janine
- Oosterhuis, Trijntje met McComb, Frank
- Oosterhuis, Trijntje met Richie, Lionel
- Oot n' Oots, The
- Ootsuki, Maki
- Ooyy (Henrik Olsson, Swedish composer and producer)
- Ooze (Swedish ambient producer Sebastian Mullaert)
- Ooze, Ivan
- Oozes, The
- OP8 (Giant Sand/Lisa Germano collaboration)
- OP8 feat. Germano, Lisa
- Opa (fusion band from Uruguay)
- Opa Cupa
- 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
- Opalo
- Opał (Polish MC)
- Opał & Gibbs
- Opania, Marian
- Opanije
- Opatovský, Robo
- Opaz
- Opbrouck, Wim (Belgian actor & musician)
- Opća opasnost
- OPcrotte
- Opeia, Cazzi
- Opeia, Cazzi & Cherry, Eagle‐Eye
- Opel, Billy
- Opel, Jackie
- Open
- Open Access (Polish power folk metal band)
- Open Air Stereo
- OPEN ARMS (UK Pop Band)
- Open Circle, The (Belgian dub techno producer)
- Open City (Punk Hardcore)
- Open Door
- Open Fifth
- Open Hand (American indie rock band)
- 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
