Lockdown (2008) was a pay-per-view (PPV) event produced by the Total Nonstop Action Wrestling (TNA) promotion, which took place on April 13, 2008 at the Tsongas Arena in Lowell, Massachusetts. It was the fourth under the TNA Lockdown chronology and fourth event in the 2008 TNA PPV schedule. Eight professional wrestling matches, two of which for championships, were featured on the card. In the tradition of Lockdown events, every match took place inside a six sided steel structure known as the Six Sides of Steel.
- Jay Lethal (c) defeated Consequences Creed, Curry Man, Johnny Devine, Shark Boy and Sonjay Dutt - Six Man Xscape match for the TNA X Division Championship
- Roxxi Laveaux defeated Angelina Love, Christy Hemme, Jackie Moore, Rhaka Khan, Salinas, Traci Brooks and Velvet Sky - Queen of the Cage match for number one contendership to the TNA Knockouts Championship
- B.G. James defeated Kip James - Six Sides of Steel Cage match
- Kaz and Super Eric defeated Black Reign and Rellik, The Latin American Xchange (Hernandez and Homicide), The Motor City Machine Guns (Alex Shelley and Chris Sabin), Petey Williams and Scott Steiner, and The Rock 'n' Rave Infection (Jimmy Rave and Lance Hoyt), - Six Team Cuffed in the Cage match
- Gail Kim and ODB defeated Awesome Kong and Raisha Saeed - Six Sides of Steel Tag Team Cage match
- Booker T and Sharmell defeated Robert Roode and Payton Banks - Six Sides of Steel Intergender Tag Team Cage match
- Team Cage (Christian Cage, Matt Morgan, Kevin Nash, Rhino and Sting) defeated Team Tomko (Tomko, A.J. Styles, Team 3D (Brother Devon and Brother Ray), and James Storm) (with Jackie Moore) - Five-on-Five Lethal Lockdown match
- Samoa Joe defeated Kurt Angle (c) - Six Sides of Steel Cage match for the TNA World Heavyweight Championship. If Joe had lost, he had to retire from professional wrestling.