Robert Thomas Letterman (born October 31, 1970) is an American film director and screenwriter. He made his directorial debut as co-director of the animated comedy film Shark Tale(2004), for which he received a nomination for the Annie Award for Writing in a Feature Production. He co-directed the animated science fiction comedy  Monsters vs. Aliens (2009).

Letterman has since transitioned into live-action filmmaking, directing the fantasy comedy film Gulliver's Travels (2010), the horror comedy film Goosebumps (2015), and the fantasy mystery film Pokémon Detective Pikachu (2019).