Lockdown (2009) was a professional wrestling pay-per-view (PPV) event produced by the Total Nonstop Action Wrestling (TNA) promotion, which took place on April 19, 2009 at the Liacouras Center in Philadelphia, Pennsylvania. It was the fifth event under the Lockdown chronology. In the tradition of Lockdown events, every match took place inside a steel structure with six sides, known as Six Sides of Steel.

The main event was a Six Sides of Steel cage match for the TNA World Heavyweight Championship, in which Mick Foley defeated the reigning champion, Sting, to win the championship. Following another tradition of Lockdown events, TNA held the annual Lethal Lockdown match, which was contested inside a steel structure with a flat roof; in this match, Team Jarrett defeated Team Angle. Two featured bouts were scheduled on the undercard. In a Philadelphia Street Fight for the TNA World Tag Team and IWGP World Tag Team Championships, Team 3D (Brother Ray and Brother Devon) defeated Beer Money, Inc. (Robert Roode and James Storm) to retain the IWGP World Tag Team and to win the TNA World Tag Team Championship. The other bout was a Doomsday Chamber of Blood match, which saw Matt Morgan defeat Abyss.