| Sammy Ogiwara (Japan) |
| The O'Haras (Borsbeek, Belgium) |
| The Orangu-Tones (Denver, Colorado) |
| The Orbitals (San Diego, California) |
| Orestes Prezza (Campinas, Brazil) |
| The Oriental Guitars (The Netherlands) |
| The Outbacks (San Francisco, California) |
| The Outer Aves (San Francisco, California) |
| Outer Wave (Huntington Beach, California) |
| The Overtones (Minneapolis, Minnesota) |