| Uncle Kracker | Rock |
| Uncle Los Music | Other |
| Uncle M | Other |
| Uncle Moondog | Other |
| Uncle Murda | Hip-Hop |
| Uncle Outrage | Electronic |
| Uncle Reece | Hip-Hop |
| Uncle Sam | Electronic |
| Uncle Tupelo | Country |
| Uncommon Nasa | Hip-Hop |
| Unconditional | Electronic |
| Unconditional Love Choir | |
| The Unconventionals | Pop |
| Un Corazón | Hip-Hop |
| Unda Flow | Hip-Hop |
| UNDEAD | Metal |
| Undefined | Metal |
| The Underachievers | Hip-Hop |
| Underbeasty (アンダービースティ) | Other |
| Under Black Clouds | Metal |
| Undercover | Rock |
| Undercover Brothers Ug | Other |
| Undercroft | Rock |
| The Underdog Project | Electronic |
| Under The Flood | Rock |
| Underflow | Rock |
| Underground Dream | |
| Underground Kingz | |
| Underground Sound of Lisbon | Electronic |
| Undergust | Other |
| Under the Influence of Giants | Rock |
| The Underlight | Other |
| Underlined | Metal |
| Under Lover | Other |
| UnderOath | Metal |
| Underset | Electronic |
| Undertaker | Metal |
| The Undertoad | Other |
| The Undertones | Rock |
| Undervienna Skies | Rock |