The Invasion was a professional wrestling storyline in the World Wrestling Federation (WWF) that began shortly after the WWF's purchase of World Championship Wrestling (WCW). It involved the WCW wrestlers "invading" WWF television in an attempt to "take over" the WWF.

The idea of a supercard featuring the two top promotions of the Monday Night Wars was considered to be a "dream match" scenario in the eyes of many fans, as it would allow the fans to see which promotion would be kayfabe superior. The angle began when Vince McMahon's son, Shane McMahon, announced on RAW that he bought WCW from under his father's nose. This led to several run-in appearances of WCW wrestlers during RAW and SmackDown! over the months after WrestleMania X-Seven.

In June 2001, the angle grew in intensity as the WWF storylines somewhat abated to make room for the central Invasion storyline. WCW and Extreme Championship Wrestling (ECW) merged to form The Alliance and challenged the WWF's control over the wrestling industry. An Inaugural Brawl took place at the WWF InVasion pay-per-view, where Stone Cold Steve Austin defected and joined the Alliance. Many inter-promotional matches occurred after the Invasion between The Alliance and the WWF, leading up to the climax of the angle at Survivor Series 2001, when Team WWF (The Rock, Chris Jericho, Big Show, The Undertaker, and Kane) defeated Team Alliance (Stone Cold Steve Austin, Kurt Angle, Rob Van Dam, Booker T, and Shane McMahon) in a Winner-Take-All match.

A very large storyline that spanned five months from June 2001 to November 2001, it has been met with heavy criticism.