- O
- OO
- OO
- OO
- OOak
- OakOat
- OatObi
- ObiObs
- ObsOce
- OceOce
- OceOct
- OctOdd
- OddOde
- OdeODM
- OdmOer
- OerOff
- OffOff
- Offogo
- OGROh
- OhOhm
- OHMOja
- OjaOka
- OkaOkt
- OktOla
- OLAOld
- OldOle
- OleOli
- OliOli
- OliOll
- OllOLU
- OluOm
- OmOme
- OmeOmo
- OMOOna
- OOne
- OneOne
- OneOne
- oneOne
- ONFOnl
- Onl
- Oon
- OonOpe
- OpeOpi
- OpiOpu
- OpuOra
- OraOrb
- OrbOrc
- OrcOrd
- OrdOrg
- OrgOri
- OriOri
- OriOrm
- OrmOrp
- OrpOrr
- OrrOrt
- OrtOsb
- OsbOsc
- OscOsl
- Osl
- OstOte
- OTFOtr
- OTROtt
- OttOur
- ourOut
- OutOut
- OutOut
- OutOVE
- OVEove
- OveOVS
- OvtOWI
- OwiOxl
- OxlOzc
- OzcOzu
- Ozuozz
- Önül, Abdurrahman & Karatüre, Celal
- Onuma, Parsley
- onumi
- Onuora, Oku
- Onur Bostancı (Alternative, Pop)
- Onural, Cengiz
- Onurr
- Onward (US band)
- Onward Brass Band (Barbarin/Cottrell, 1960-)
- Onward to Olympas
- Onward, etc.
- Onyanko Club
- Onyeabor, Charles
- Onyeabor, William
- Onyioha, Oby
- Onyria (Oniria)
- Onysus
- ONYVAA
- Onyx (New York hardcore rap group)
- Onyx (Israeli psytrance DJ Yaniv Goldfarb)
- Onyx (IDM artist, track "Under Pressure")
- Onyx & Dope D.O.D.
- Onyx Collective
- Onyx feat. ASAP Ferg & Price, Sean
- Onyx feat. DMX
- Onyx feat. Dope D.O.D.
- Onyx feat. Genovese
- Onyx feat. Havoc
- Onyx feat. Makem Pay
- Onyx feat. Papoose & Cormega
- Onyx feat. Reks
- Onyx feat. Snak the Ripper
- Onyx feat. X1
- Onyx, PTX & Domestic
- Onza (Spanish prog and fusion band)
- Onza (Spanish rock band.)
- Onze‐Mots
- Onze:20
- OOBE (Polish Rock Band)
- Ooberfuse
- Ooberman
- Oobie (Tenaia Sanders)
- Oobik & the Pucks
- OOcarpet (South Korean band)
- Oodaredevil (Yeat collaborator aka DareDevil)
- ooes
- ooes, Pantera Blue
- oofoe
- Oogie
- Ooh La La
- Oohashi, Takuya
- Oohlas, The
- OOHYO
- ooi (German indie pop band)
- Ooi, Imee
- OOJA, Ms. (hiphop)
- OOJA, Ms. feat. LATINO, EL
- Ookay
- Ookay & Byers, Piper
- Ookay & Cesqeaux
- Ookay & Chime
- Ookay & JSTJR
- Ookay & Linney
- Ookay & Sinjin
- Ookay feat. Byers, Piper
- Ookay feat. Vance, David
- Ookla the Mok (filk group)
- Ooklah the Moc
- 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
- Oompie Koerier
- 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
