- O-Town
- O.A.R.
- O.C.
- O.T. Genasis
- O.Torvald
- O.W.S.
- Oak
- Oasis
- Obey the Brave
- Oceana
- Oceana (Band)
- Ocean Jet
- Oceanlab
- Oceano
- Oceans Ate Alaska
- Oceans Divide
- OCTiV
- October Fall
- ODESZA
- Ofelia K
- Ofenbach
- Ofenbach & Portugal. The Man
- Off Bloom
- Offer Nissim
- Offset
- Offspring
- Of Mice & Men
- Of monsters and men
- Of Montreal
- Ofra Haza
- Of the Wand & the Moon
- of Verona
- OG3NE
- Oh, Hush!
- Oh, Sleeper
- Oh, Weatherly
- Oh Honey
- Oh Land
- Oh The Larceny
- Oh Wonder
- Oingo Boingo
- Oi Polloi
- Oi Va Voi
- Okean Elzy (Океан Ельзи)
- OK Go
- Okkervil River
- Ol' Dirty Bastard
- Ola
- Olafur Arnalds
- Olafur Arnalds and Arnor Dan
- Ola Svensson
- Old Crow Medicine Show
- Old Daisy
- Old Man Shattered
- Oleander
- Oleg Chubykin
- Olexandr Ponomariov
- Olexesh
- Olga Tanon
- Oliver Boyd and the Remembralls
- Oliver Heldens
- Oliver Heldens & Shaun Frank
- Oliver Koletzki
- Oliver Moldan
- Oliver Spalding
- Oliver Tree
- Oliver Trolley
- Olivia Holt
- Olivia Millerschin
- Olivia Newton-John
- Olivia O'brien
- Olivver The Kid
- Olly Murs
- Olson And Lary
- Olsson
- Omar & The Howlers
- Omara Portuondo
- Omarion
- Omar Naber
- Omega El Fuerte
- Omega Lithium
- OmenXIII
- Omer Bhatti
- Omi
- Omkara
- Omnia
- OMNIMAR
- Omnium Gatherum
- On-The-Go
- Once a liar, always a liar) (Story Untold
- One Bit
- One Bit & Noah Cyrus
- One Direction
- One eskimO
- One Less Reason
- One Love
- One Night Only
- Oneohtrix Point Never
- One OK Rock
- OneRepublic
- One Week Wonder
- One Year Later
- Onion
- on level
- Only The Young
- ONUKA
- Onyx
- Oomph!
- Oona
- Oonagh
- Open Chapter
- Open Hand
- Openside
- Opeth
- Opia
- Optimus
- Opus
- Opus III
- Oranger
- Orchestral manoeuvres in the dark (OMD)
- Orden Ogan
- Ordo Rosarius Equilibrio
- Oren Lavie
- Orgy
- Orianthi
- Orion Rigel Dommisse
- Orishas
- Orleans
- Ortal
- Oscar And The Wolf
- Oscar Benton
- Oscarcito
- Oscar Zia
- Oskar Enestad
- Osmani Garcia
- Osmonds, the
- Os Mutantes
- Ost+Front
- Oswaldo Montenegro
- Otep
- Other Lives
- Otherwise
- Otilia
- Otis Redding
- Oto Nemsadze
- Ottawan
- Otto Knows
- Our Lady Peace
- Our Last Night
- Ourlives
- Outburst, The
- Outfield, the
- OutKast
- Outlandish
- Outline in color
- Outloudz
- Out With The Old
- Overkill
- Ovi
- Ovidiu Anton
- Owl City
- Ozark Mountain Daredevils
- Ozuna
- Ozzie
- Ozzy Osbourne
