Horton Hears a Who! was adapted into a computer-animated feature-length film of the same name in 2008, using computer animation from Blue Sky Studios, the animation arm of 20th Century Fox. It was released on March 14, 2008.^[6] Jim Carrey voices Horton, Carol Burnett voices the Sour Kangaroo, who is called 'Kangaroo', and Steve Carell voices the Mayor of Who-ville (now named Ned McDodd 

On March 2, 2012, Universal Studios and Illumination Entertainment released a 3-D CGI film based upon the book. The release coincided with the 108th birthday of Seuss, who died at 87 in 1991. The cast includes Danny DeVito as the Lorax, Zac Efron as Ted (the boy in the book), and Ed Helms as the Once-ler. The film includes several new characters: Rob Riggle as villain O'Hare, Betty White as Ted's Grammy Norma, and Taylor Swift as Audrey, Ted's romantic interest