Horton Hears a Who! (film)

Horton Hears a Who! is a 2008 American animated adventure comedy film based on the 1954 children's book by Dr. Seuss. Produced by Blue Sky Studios, the film was directed by Jimmy Hayward and Steve Martino and written by Cinco Paul and Ken Daurio. It stars the voices of Jim Carrey and Steve Carell as Horton the Elephant and Mayor Ned McDodd, respectively, alongside Carol Burnett, Will Arnett, Seth Rogen, Dan Fogler, Isla Fisher, Jonah Hill, and Amy Poehler. The plot follows Horton, an eccentric elephant who discovers the city of Whoville, led by Mayor McDodd, on a tiny speck. Horton begins a journey to take the speck to safety while a group of animals led by the Kangaroo attempt to stop him.

The film is the fourth screen adaptation of the book, following the 1970 Chuck Jones television special, the 1987 Soviet animated short, and the 1992 Russian animated short. Production began in 2005 after executive producer Chris Meledandri secured the rights to the book from Seuss's widow Audrey Geisel, who provided the studio with Seuss's original sketches and materials and was credited as an executive producer. Recurring Blue Sky collaborator John Powell composed the film's musical score.

Horton Hears a Who! was released theatrically in the United States on March 14, 2008, by 20th Century Fox. The film was well-received by critics, who praised its writing, visuals, and faithfulness to the source material, and grossed $298 million on a budget of $85 million. Horton Hears a Who! was the first Dr. Seuss film adaptation to be fully animated using CGI and the second to feature Jim Carrey after How the Grinch Stole Christmas (2000).