Obsessed is a 2009 American psychological thriller film directed by Steve Shill and written by David Loughery. Starring Idris Elba, Beyoncé, and Ali Larter alongside Bruce McGill, Jerry O'Connell, and Christine Lahti, the film follows Lisa Sheridan (Larter), an office temp who develops unrequited feelings for her boss, Derek Charles (Elba), and repeatedly attempts to seduce him. Derek's wife, Sharon (Beyoncé), learns of Lisa's escalating behavior and suspects her husband is having an affair.

Obsessed premiered at the School of Visual Arts on April 23, 2009, and was theatrically released in the United States the following day. The film was panned by critics, who criticized the absence of an explanation for Lisa's obsession with Derek, failure to explore the potential theme of interracial conflict between Lisa and the Charles family, and the fact that Derek did not yield to Lisa's seduction. It also drew unfavorable comparisons to Fatal Attraction (1987), although the climactic fight scene between Beyoncé and Larter was widely praised, winning the MTV Movie Award for Best Fight at the 2010 MTV Movie Awards. Despite the critical reception, the film was a modest success at the box office, grossing $73.8 million against its $20 million budget.