- O
- OO
- OO
- OO
- OO
- OOak
- OakObe
- ObeObl
- oblObs
- ObsOce
- OceOch
- OchOCT
- OctODC
- ODCOdd
- OddOde
- OdeODU
- ODUof
- ofOFF
- OffOFK
- OfMOgr
- OgrOh
- OhOhi
- OhiOim
- OimOK
- OKOke
- OkeOl
- OlOl
- OlaOld
- OldOle
- OleOlg
- OlgOli
- OliOli
- OliOls
- OlsOma
- OmaOma
- OmaOme
- OmeOmn
- OmnOn
- OnOne
- OneOne
- OneOne
- OneOne
- OneOnk
- OnkOno
- OnoOny
- OnyOos
- OosOpe
- OpeOPL
- OPMOpu
- OpuOra
- OraOrb
- OrbOrc
- OrcOrd
- OrdOre
- OreOri
- OriOri
- OriORK
- OrkOro
- OroOrq
- OrqOrr
- OrrOrt
- OrtOsa
- OsaOsc
- OscOSK
- OskOss
- OssOta
- OtaOth
- OthOtt
- OttOtt
- OttOur
- OurOut
- OutOut
- OutOut
- OutOv
- OvOve
- OveOVE
- OVEOwe
- OweOwl
- OwlOxm
- OxmOza
- OzaOzo
- OzoOzz
- Oosterhuis, Trijntje feat. Dulfer, Candy
- Oosterhuis, Trijntje met McComb, Frank
- Oosterhuis, Trijntje met Richie, Lionel
- Oot n' Oots, The
- Oota, Michihiko
- Ootam (French rapper)
- Ootsuki, Maki
- Ooyy (Henrik Olsson, Swedish composer and producer)
- Ooyy & HDBeenDope
- Ooze, Ivan
- Oozes, The
- Oozing Wound
- 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 Eskar
- Opal In Sky
- Opal Onyx
- Opalo
- Opał (Polish MC)
- Opał & Gibbs
- Opambuo International Band of Ghana
- Opania, Marian
- Opanije
- Opaque (drum n bass DJ/producer Paul Dolby aka Seiji)
- 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 Chapter
- 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 & Segal, Kenny
- Open Mike Eagle & White, Paul
- Open Mike Eagle feat. Aesop Rock and Diamond D
- 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. 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
- Open Mind, The (68–73 UK psychedelic rock band)
- Open Minded
- Open Palms
- Open Road (US bluegrass group)
- Open Sails
- Open Sea, The
- Open Season (Australian RAC band)
- Open Sky
- Open Skyz
- Open the Door for Three
- Open the Skies
- Open Trench
- Open University, The
- Open Up and Bleeds, The
- Open, The
- Openside
- Opensight (Metal)
- Opensouls
- Opera (Polish group)
- Opera Alaska
- Opera Australia
- Opéra Bastille, Orchestre de l’, Chung, Myung-Whun
- Opera Chaotique
- Opera Diabolicus (Doom/Black/Death Metal Swedish Band)
- Opera Familia
