I Know Who Killed Me is a 2007 American psychological thriller film directed by Chris Sivertson and written by Jeff Hammond. Starring Lindsay Lohan, the film follows a young woman who is abducted and tortured by a sadistic serial killer. After surviving the abduction, she insists that her identity is that of another woman. The film also features Julia Ormond, Neal McDonough, Brian Geraghty, Garcelle Beauvais and Spencer Garrett in supporting roles.

I Know Who Killed Me was theatrically released on July 27, 2007, by TriStar Pictures. The film received negative media coverage during production and upon its release, as Lohan publicly struggled with drug addiction and other personal issues. It was promptly deemed a failure and called one of the worst films ever made, being the most awarded at the 28th Golden Raspberry Awards, winning seven of eight nominations. It did, however, attain a more successful home video performance, having almost quadrupled its box office gross in estimated domestic DVD sales.

I Know Who Killed Me subsequently developed a cult following that has reexamined it as a modern giallo, and several screenings of it have been put together by historic theaters and film festivals.