- 1 OneRepublic
- 2 One Direction
- 3 Oasis
- 4 Owl City
- 5 O-Zone
- 6 Oh Wonder
- 7 Oh The Larceny
- 8 One Voice
- 9 Odesza
- 10 One-T And Cool-T
- 11 Of Monsters And Men
- 12 Old Man Canyon
- 13 Our Lady Peace
- 14 Oceanlab
- 15 Ocean Colour Scene
- 16 Oh No! Oh My!
- 17 Obituary
- 18 O.A.R.
- 19 Oceana
- 20 Outloud
- 21 Orbital
- 22 of Montreal
- 23 Ozomatli
- 24 Overground
- 25 OZMA
- 26 Our Last Night
- 27 O-Town
- 28 Outkast
- 29 Outlawz
- 30 Onyx