- O
- OO
- OO
- OO
- OO
- oOak
- OakObe
- ObeObl
- OBLOC
- OCOce
- OceOck
- OckOct
- OctOdd
- OddOde
- OdeOdo
- OdoOes
- OesOff
- OffOff
- OffOgi
- OgiOh
- OhOhi
- OhiOir
- OisOK
- OKOki
- OkiOl
- OlOld
- OldOld
- OldOle
- OleOli
- OliOli
- OliOll
- OllOls
- OlsOma
- OmaOme
- OmeOmn
- OmnOn
- OnOnd
- OndOne
- OneOne
- Oneone
- ONEOni
- OniOnl
- OnlOnw
- Ony
- OooOpe
- OpeOpi
- OpiOpu
- OpuOra
- OraOrb
- OrbOrc
- OrcOrc
- OrcOre
- OreOrh
- OriOri
- OriOrk
- OrkOrn
- OrnOrq
- OrqOrr
- OrsOrt
- OrtOsb
- OsbOsc
- OscOsl
- OslOst
- OstOtC
- OTEOti
- OTIOtt
- Ottotx
- OtyOur
- OurOut
- OutOut
- OutOut
- OutOVE
- Oveove
- oveOvn
- OvnOwe
- OweOxf
- OxfOz
- OzaOzo
- OzoOZZ
- O.G. & YONII
- O.G. Black
- O.G. Black feat. Voltio
- O.G. feat. Nimo
- O.G. Pezo
- O.G. Pezo & Lucio101
- O.G. Pezo, LockeNumma19 & Mista Meta
- O.G.C. (US hardcore rap group Originoo Gunn Clappaz)
- O.M.G.
- o.n.a.
- O.O.D., OOD, Ood
- O.P.KING
- O.R.k.
- O.R.k. feat. Tankian, Serj
- O.R.O. (Italian pop)
- O.R.U. Worship (Oral Roberts University)
- O.S., Arun (Carnatic Vocalist)
- O.S.T.R. (Polish rapper, musician and producer)
- O.S.T.R. & Hades
- O.S.T.R. & Hades (Duo of two polish rappers)
- O.S.T.R. & Marco Polo (Polish rapper and canadian musician producer)
- O.S.T.R. & Marco Polo
- O.S.T.R. & Sofa
- O.S.T.R. feat. El da Sensei
- O.S.T.R. feat. El da Sensei & Fresh, Dan
- O.S.T.R. feat. Evidence
- O.S.T.R. feat. Gibbs
- O.S.T.R. feat. Green
- O.S.T.R. feat. Hades
- O.S.T.R. feat. J, Brother
- O.S.T.R. feat. Kali
- O.S.T.R. feat. Main Flow & Kaze
- O.S.T.R. feat. Młody O
- O.S.T.R. feat. Murray, Keith & Kochan
- O.S.T.R. feat. Nash, Steve & Sacha Vee
- O.S.T.R. feat. Playground Zer0
- O.S.T.R. feat. Sadat X & Cadillac Dale
- O.S.T.R. feat. Sarius
- O.T. Genasis
- O.T. Genasis feat. Young Dolph
- O.T. Quartet
- O.T.R.
- O.Torvald
- O.W.L.
- O.WHEN (Singer-songwriter)
- O.Z (Canadian hip hop)
- O.Z (Mongolian R&B, Pop singer)
- O'Bannon, Dillon
- O'Bir, Jon (Trance/Progressive-Trance DJ & producer from Nottingham, UK and based in Manchester, UK)
- O'Bir, Jon feat. Fisher
- O'Blivion, Monty (LA darkwave)
- O'Boy (french rapper)
- O'Boyle, Maeve
- O'Boyle, Sean
- O'Brien Sisters, The
- O'Brien-Docker, Ian
- O'Brien, Andrew James
- O'Brien, Charlie (singer and filmmaker)
- O'Brien, Chris (US Singer-songwriter)
- O'Brien, Connor
- O'Brien, Ethan
- O'Brien, James
- O'Brien, Joseph (production music composer)
- O'Brien, Joseph (Christian Artist)
- O'Brien, Michael (US AOR/christian vocalist)
- O'Brien, Michael (US christian singer/songwriter, member of Newsong)
- O'Brien, Mollie (folksinger)
- O'Brien, Paddy (Irish country singer)
- O'Brien, Paul
- O'Brien, Rich
- O'Brien, Sinead (Irish punk poet)
- O'Brien, Tim & Scott, Darrell
- O'Brien, Tim & Scott, Darrell
- O'Brien, Trisha
- O'Callaghan, Erin
- O'Callaghan, John & Larkin, Betsie
- O'Callaghan, John feat. Cathy Burton
- O'Casan
- O'Clock, Apes
- O'Connell, Krista
- O'Connor, Alex & Shan, Charlie
- O'Connor, Hazel
- O'Connor, Hazel & Barra, Cormac de
- O'Connor, Hazel, Hirst, Clare & Sarah Fisher
- O'Connor, Katie (Songwriter from Galway, Ireland)
- O'Connor, Kim
- O'Connor, Mark's Hot Swing Trio
- O'Connor, Michael
- O'Connor, Nora
- O'Connor, Tony (New Age composer)
