Oasis (UK; Brit Pop)
Oathean (Korea; Melodic Black/Melodic Death)
Obituary (USA; Death)
Obsessed (USA; Doom)
Obsession (USA; Heavy Metal)
Obtest (Lithuania; Black/Heavy Metal/Folk Metal)
Obus (Spain; Heavy Metal)
Occult (Holland; Thrash)
Ocean (Germany; Post Metal)
Ocean Colour Scene (UK; Brit Pop)
Oceans Of Slumber (USA; Prog Metal)
October Tide (Sweden; Doom/Death)
Odd Logic (USA; Prog Metal)
Odes Of Ecstasy (Greece; Sympho Death)
Odin (USA; Heavy Metal)
Odium (Germany; Heavy Metal/Thrash)
Offenbach (Canada; Blues Rock/Hard Rock)
Offspring (USA; Pop Punk)
Of Montreal (USA; Baroque Pop/Indie Pop/Glam/Neo-Psychedelic/Retro Rock)
Ohio Players (USA; Soul/Funk)
Ohrenfeindt (Germany; Hard Rock)
Oingo Boingo (USA; New Wave)
OK Go (USA; Indie/Power Pop/Pop Rock)
Old Man's Child (Norway; Black)
Oliver/Dawson Saxon (UK; Hard'N'Heavy)
Olympic (Czechoslovakia; Beat/Pop Rock/Hard Rock)
Omar & The Howlers (USA; Blues Rock)
Omega (Hungary; Beat/Hard Rock/Space Rock/New Wave)
Omen (USA; Power)
Ondskapt (Sweden; Black)
Oneira (Italy; Art Rock)
OneRepublic (USA; Pop Rock/Indie)
Onkel Tom Angelripper (Germany; Punk Thrash)
Onmyo-Za (Japan; Heavy Metal)
Onslaught (UK; Thrash)
On Thorns I Lay (Greece; Death/Doom / Gothic Metal)
Oomph! (Germany; Industrial)
Open Mind (UK; Psychedelic)
Opera IX (Italy; Black)
Opeth (Sweden; Death/Prog Metal/Prog Rock)
Opprobrium (USA; Death/Thrash)
Opus (Austria; Pop Rock)
Opus Avantra (Italy; Progressive)
Orange Goblin (UK; Stoner)
Orang-Utan (UK; Hard Rock)
Orchestral Manoeuvres In The Dark (UK; New Wave/Synth Pop)
Orden Ogan (Germany; Power)
Order (Switzerland; Hard'N'Heavy)
Ordo Rosarius Equilibrio (Sweden; Apocalyptic Folk/Martial Industrial)
Oregon (USA; Jazz Rock/ Fusion)
Oresund Space Collective (Denmark; Space Rock)
Orgy (USA; Industrial)
Orianthi (Australia; Blues Rock/Hard Rock/Pop Rock)
Orleans (USA; Soft Rock)
Orphan (Canada; AOR)
Orphanage (Holland; Doom/Death/Gothic Metal)
Orphaned Land (Israel; Oriental Metal)
Orpheus Omega (Australia; Melodic Death)
Osanna (Italy; Progressive)
Oscar Benton (Holland; Blues/Pop Rock)
OSI (USA; Prog Metal)
Osibisa (UK; Afro Rock)
Osiris (Bahrain; Progressive)
Osmonds (USA; Pop Rock)
Os Mundi (Germany; Psychedelic/Jazz Rock)
Os Mutantes (Brazil; Tropicalia)
Ostrogoth (Belgium; Heavy Metal)
Otep (USA; Nu Metal)
O Terco (Brazil; Progressive)
Otis Redding (USA; Soul)
Otis Rush (USA; Blues)
Ougenweide (Germany; Folk Rock)
Our Lady Peace (Canada; Alternative)
Outfield (UK; New Wave/Power Pop/Pop Rock)
Outlaws (USA; Southern Rock)
Out Of Focus (Germany; Kraut/Jazz Rock)
Overdose (Brazil; Thrash)
Overkill (USA; Thrash)
Overland (UK; Melodic Rock)
Oz (Finland; Heavy Metal)
Ozark Mountain Daredevils (USA; Country Rock)
Ozric Tentacles (UK; Psychedelic)
Ozzy Osbourne (UK; Heavy Metal)