The Cat in the Hat (also known as Dr. Seuss' The Cat in the Hat) is a 2003 American fantasy comedy film directed by Bo Welch in his directorial debut and written by Alec Berg, David Mandel and Jeff Schaffer. Loosely based on Dr. Seuss's 1957 book of the same name, it was the second and final live-action Dr. Seuss adaptation after How the Grinch Stole Christmas (2000). The film stars Mike Myers in the title role along with Alec Baldwin, Kelly Preston, Dakota Fanning, Spencer Breslin, Amy Hill and Sean Hayes in supporting roles.

Dr. Seuss’ The Cat in the Hat was released in theaters on November 21, 2003, in the United States by Universal Pictures and internationally by DreamWorks Pictures. It grossed $133.9 million against a budget of $109 million. The film received largely negative reviews from critics, but it has since developed a mild cult following and some positive critical retrospectives.

After the film’s release, Seuss's widow, Audrey Geisel, prohibited any further live-action adaptations of her husband's works during her lifetime, resulting in the cancellation of a sequel based on The Cat in the Hat Comes Back. All adaptations have since been produced using computer animation. Warner Bros. Pictures Animation is developing another adaptation, and is scheduled to be released in 2026.