- Undecimber (gothic metal)
- Undeclinable
- Undeclinable Ambuscade
- Undenyable
- Under (San Francisco downtempo band)
- Under (Rock band from New Zealand / Australia / Hong Kong)
- Under Black Helmet (techno producer)
- Under Byen (Danish band)
- Under Delusion
- Under Eden
- Under Electric Light
- Under Moonlight Sadness
- Under the Black Shores (Deathcore from Paris, France)
- Under the Church (death metal)
- Under the Flood
- Under the Gallows (UtG)
- Under the Influence
- Under the Influence of Giants
- Under the Mountain
- Under the Oak (US folk artist from Philadelphia, PA)
- Under the Pledge of Secrecy
- Under The Rug
- Under the Scythe
- Under the Symphony (Argentinian rock band)
- Under Their Church
- Under Threat (Melodic Death Metal)
- Under Two Flags
- Underachievers, The (US rap group)
- Underachievers, The (hardcore punk)
- Underaiki
- Underberg, Andrew
- Underberg, Andrew, Haft, Sam, David, Keith & Roman, Blake
- Undercast (Undercast is an alternative rock band based in Sydney, Australia.)
- Undercatt
- Undercover (UK dance group)
- Undercover (SoCal rock band)
- UnderCover (Psytrance; Adam Belo & Almog Shmuel)
- Undercover Agency
- Undercover Agent & Kriminal, The
- Undercover Brothers Ug (Uganda)
- Undercover Hippy, The
- Undercroft (Chilean death metal band)
- Underdog (New York hardcore group)
- Underdog Project, The (German‐Belgian dance group)
- Underdog Project, The feat. Sunclub, The
- Underdog Project, The vs. Sunclub, The
- Underdown, Jon
- Underfish
- Underfound
- Undergang (Danish death metal)
- Undergång (Swedish crossover band)
- Undergods, The (Canibus & Keith Murray)
- Undergods, The feat. Tech N9ne
- Underground Dance Artists United for Life
- Underground Dance Artists United for Life feat. Tucker, Barbara
- Underground Fly
- Underground Kingz feat. Kool Ace & Too Short
- Underground Lovers
- Underground Resistance (Detroit techno collective)
- Underground Samba Lapa
- Underground Society (Brutal Hardcore from Rennes, France)
- Underground Sound of Lisbon
- Underground Sound Society, The
- Underground Springhouse
- Underground Youth, The (UK post‐punk band)
- Underground, Glenn
- Undergrunn (Norwegian hip hop group)
- Undergrunn feat. KingSkurkOne
- Undergrunn feat. Kode.59
- UNDERHER (UNDERHER was created by Khaled Bess in 2017)
- Underhill, Adrian
- Underhill, Emily
- Underjordiska Lyxorkestern
- Underlined (industrial metal)
- Underminded
- Undermine (Thrash/Death metal band from Argentina)
- Undermine the Supremacy
- Underneath (metallic hardcore)
- Underneath the Gun
- Underoath
- Underoath feat. Ghostemane
- Undersave
- Underscore Orkestra, The (Balkan/Klezmer/Hot Jazz/Americana/Swing band from Portland, Oregon)
- underscores (glitch hop/pop artist)
- underscores (feat. gabby start)
- underscores feat. 8485
- underscores feat. gabby start
- underscores feat. Knapsack
- underscores feat. Song, Inho
- underscores feat. Young, Maxwell
