Runaway Brain is a 1995 American animated comedy horror short film produced by Walt Disney Feature Animation. Featuring Mickey Mouse and Minnie Mouse, the short centers on Mickey attempting to earn money to pay for an anniversary gift for Minnie. He responds to an advertisement to work for Dr. Frankenollie, but finds that the doctor is looking for a donor to switch brains with the monster he created. Featuring animation by animator Andreas Deja, it was first released in 1995 attached to North American theatrical showings of A Kid in King Arthur's Court and in 1996 attached to international theatrical showings of A Goofy Movie. It would be the final original Mickey Mouse theatrical animated short until Get a Horse! in 2013.

The short received a mixed reception from audiences, and was nominated for the Academy Award for Best Animated Short Film at the 68th Academy Awards, losing to the Wallace and Gromit short A Close Shave. Later references to the cartoon have been made in Disney related media such as the video game Kingdom Hearts 3D: Dream Drop Distance.