The War with Grandpa is an upcoming American family comedy film directed by Tim Hill and starring Robert De Niro, Christopher Walken, and Oakes Fegley. It was based on the novel of the same name by Robert Kimmel Smith.

Plot

Forced to give up his room to his grandfather (De Niro), a scheming boy (Fegley) devises a series of outrageous pranks in an attempt to make him move out.