Under Siege was a professional wrestling event produced by Impact Wrestling. It took place on May 15, 2021 at the Skyway Studios in Nashville, Tennessee. It aired exclusively on Impact Plus. Nine matches were contested at the event.
| Actor | Role |
|---|---|
 Quinn OjinnakaMoose | Moose |
 Chris BeyChris Bey | Chris Bey |
 Josh HarterChris Sabin | Chris Sabin |
 Matthew CardonaMatt Cardona | Matt Cardona |
 Samuel Alton JohnstonSami Callihan | Sami Callihan |
 Trey McBrayerTrey Miguel | Trey Miguel |
 Eric MaherEddie Edwards | Eddie Edwards |
 David Stephen Finlay IIIDave Finlay | Dave Finlay |
 Joseph RobinsonJuice Robinson | Juice Robinson |
 Tyson SmithKenny Omega | Kenny Omega |
 Drew HankinsonDoc Gallows | Doc Gallows |
 Chad AllegraKarl Anderson | Karl Anderson |
 Deonna KuprykDeonna Purrazzo | Deonna Purrazzo |
 Kimberly Ann FrankeleKimber Lee | Kimber Lee |
 Jessica CricksHavok | Havok |
 Joshua LemayJosh Alexander | Josh Alexander |
 Riley VigierEl Phantasmo | El Phantasmo |
 Kiera HoganKiera Hogan | Kiera Hogan |
 Latasha HarrisTasha Steelz | Tasha Steelz |
 Patricia GreshamJordynne Grace | Jordynne Grace |
 Rachael ElleringRachael Ellering | Rachael Ellering |
 William MorrisseyW. Morrissey | W. Morrissey |
 Willie McClinton Jr.Willie Mack | Willie Mack |