A Boy and His Sister: A Dexter's Laboratory Movie

A Boy and His Sister: A Dexter's Laboratory Movie is a 2026 American computer-animated adventure comedy film directed by Genndy Tartakovsky (creator of the original series) and written by series writers Paul Rudish, Amy Keating Rogers, Michael Ryan, and Walt Dohrn. Candi Milo, Kat Cressida, Eddie Deezen, Jeff Bennett and Kath Soucie reprise their roles from the series; accompanied by Jim Parsons, Mckenna Grace, Charlize Theron, Martin Short, Dan Aykroyd and Christopher Walken. This is the first computer-animated feature film from Cartoon Network Studios, with co-production by Warner Animation Group.

A Boy and His Sister had its premiere in Hollywood on March 25, 2026, and was released theatrically in the United States for the series' 30th anniversary on April 10, by Warner Bros. Pictures. It grossed $150.2 million on a $90 million budget. The film was met with positive reviews, with critics praising the voice cast, humor, and heart, while the choice of computer-animation was mixed.

Plot
Dexter, having graduated from Huber Elementary and moving to Huber University, receives a Nobel prize for his invention that ends world hunger; an invention he had been working in secrecy due to his childish, older sister, DeeDee, who had ruined several of his inventions from the start.