Michael Myers is a fictional character from the Halloween series of slasher films. He first appears in John Carpenter's Halloween (1978) as a young boy who murders his older sister, then fifteen years later returns home to murder more teenagers. In the original Halloween, the adult Michael Myers, referred to as The Shape in the closing credits, was portrayed by Nick Castle for most of the film, with Tony Moran and Tommy Lee Wallace substituting in during the final scenes. He was created by Debra Hill and John Carpenter. Michael Myers has appeared in eight films, as well as novels, a video game and several comic books.

The character is the primary antagonist in the Halloween film series, except Halloween III: Season of the Witch, which was not connected in continuity to the rest of the films. Since Castle, Moran, and Wallace put on the mask in the original film, six people have stepped into the role. There have been no actors to portray the character in consecutive films, with a new actor filling the role in each succeeding film; only one actor has portrayed the character more than once. Michael Myers is characterized as pure evil, whether directly in the films, by the filmmakers who created and developed the character over eight films, or random participants in a survey.