Touch of Evil is a 1958 American film noir written and directed by Orson Welles, who also stars in the film. The screenplay was loosely based on the contemporary Whit Masterson novel Badge of Evil (1956). The cast included Charlton Heston, Janet Leigh, Joseph Calleia, Akim Tamiroff and Marlene Dietrich.

Universal-International commissioned the film adaptation of the novel in April 1956. Albert Zugsmith was selected as producer, who then hired television writer Paul Monash to write the script. Heston was brought on board to star in January 1957 and suggested that Welles direct the project. Welles was hired to direct and star, as well as re-write the script. Filming started the next month and wrapped in April. During the film's post-production, creative differences between Welles and Universal executives arose and Welles was forced off the film. Subsequently, Universal-International revised the film's editing style to be more conventional and ordered re-shoots to be made in November 1957. In response to the new version, Welles wrote a 58-page memo in which he elaborately outlined his creative vision for the film and asked that his version be restored.

Initially dismissed by film critics, Touch of Evil found popularity among European audiences and won top awards at the 1958 Brussels World Film Festival. During the 1970s, its reputation was renewed and it is now widely regarded as one of Welles's best motion pictures and one of the best classic-era noir films as well as one of the last. Touch of Evil was re-edited according to Welles's original vision, as outlined in his memo, in 1998.

In 1993, the film was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant".