- O
- OO
- OO
- OOak
- OakObe
- ObeObs
- ObsOce
- Oceoch
- OchOct
- OctOde
- OdeOdo
- OdoOfa
- OfaOff
- OffO
- OOha
- OhaOiz
- OizOKA
- OKAOl
- OlOld
- OldOle
- OleOli
- OliOli
- OliOls
- OlsOma
- OmaOml
- OmmOn
- OnOne
- OneOne
- OneOne
- OneOnl
- OnlOny
- OnyOpe
- OpeOpi
- OpiOra
- OraOrb
- OrbOrc
- OrcOre
- OreOri
- OriOrk
- OrkOro
- OrpOrr
- OrrOrw
- OrwOsb
- OsbOsk
- OskOst
- OstOth
- OthOtt
- OttOur
- OurOut
- OutOut
- OutOva
- OvaOve
- OveOwe
- OweOxb
- Oxe
- OzeOZZ
- Only Seven Left (Dutch pianorock band)
- Only Son
- Only Sons
- Only Sun (@onlysunofficial)
- Only the Family
- Only the Family & Booka600
- Only the Family & Lil Durk
- Only the Family feat. Doodie Lo
- Only the Family feat. King Von
- Only the Family feat. Lil Durk
- Only the Family feat. Lil Durk & King Von
- Only the Family feat. Lil Durk, Tee Grizzley & Sada Baby
- Only the Family feat. OTF Ikey
- Only the Family feat. Park Hill & OTF Ikey
- Only The Poets
- Only this time (Japanese group)
- Only Twin
- Only, Brady
- Only, Jerry
- Only, The
- Onlybino!
- OnlyBobbyLee
- Onlyfriend
- OnlyOneOf (South Korean boy group)
- Onmens (Belgian duo)
- Onmyo-za
- ONO (Chicago experimental band)
- Ono, Daisuke
- Ono, Erena
- Ono, Lisa (Brazilian-Japanese bossa nova singer)
- Ono, Masatoshi
- Ono, Yoko (Japanese-American musician and artist)
- Ono, Yoko feat. Audé, Dave
- Ono, Yoko feat. Death Cab for Cutie
- Ono, Yoko feat. Lennon, Sean
- Ono, Yoko feat. Miike Snow
- Ono, Yoko feat. Penguin Prison
- Ono, Yoko feat. Peter Bjorn and John
- Ono, Yoko feat. Portugal. The Man
- Ono, Yoko feat. Sparks
- Ono, Yoko feat. Tenaglia, Danny
- Ono, Yoko Plastic Ono Band
- Ono, Yoko/IMA
- Onoe Caponoe
- onoken
- Onokio
- Önol, Onat
- Onono, Ben
- Onorata
- ONR.
- Onra (French producer/beatmaker Arnaud Bernard)
- Onra feat. B, Reggie
- Onrust (Dutch 2000s black metal)
- Onrust (Belgian post-metal band)
- Onsa Media (a group of musicians, who records covers mainly and sometimes original songs and parodies also)
- ONSatan
- Onsind (acoustic pop punk band)
- Onslaught (UK punk/thrash/speed metal band)
- Onslow (Alternative rock band)
- Ontaneda, Sara
- ontologics
- Ontuak
- Onuabuobi, Victor (Nigerian gospel singer)
- Onuka
- Onuki, Taeko
- Onukwulu, Ndidi
- Onuma, Parsley
- onumi
- Onur Bostancı (Alternative, Pop)
- Onural, Cengiz
- Onurr
- Onward (US band)
- 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 artist/DJ Yanniv Gold Farb)
- 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
