César Díaz (born 20 September 1978) is a Belgian-Guatemalan film director, screenwriter and editor.

Born and raised in Guatemala City, Díaz moved to Belgium in 1998 as a student at the Free University of Brussels. After developing an interest in filmmaking, he enrolled at the La Fémis film school in Paris and studied screenwriting. Since the mid-2000s, Díaz has worked on a number of documentary films, before making his feature-length debut in 2019 with Our Mothers. The film premiered at the 2019 Cannes Film Festival, where Díaz won the Caméra d'Or.