James Dalton Trumbo (December 9, 1905 – September 10, 1976) was an American screenwriter and novelist known for scripting many award-winning films, such as Roman Holiday (1953), Exodus, Spartacus (both 1960), and Thirty Seconds Over Tokyo (1944). Trumbo was one of the Hollywood Ten, a group of film industry professionals who were blacklisted for refusing to testify before the House Un-American Activities Committee (HUAC) in 1947 during its investigation of Communist influences in Hollywood.

Despite the blacklist, Trumbo continued to work under pseudonyms or using other authors' names, clandestinely contributing to major films. His uncredited work won two Academy Awards for Best Story: Roman Holiday, awarded to a front writer, and The Brave One (1956), awarded to a pseudonym used by Trumbo. The public crediting of Trumbo for Exodus and Spartacus in 1960 marked the beginning of the end of the Hollywood Blacklist for him and other affected screenwriters. Nearly 60 years after the fact, in 2011, the Writers' Guild finally gave him full credit for Roman Holiday.

Before his screenwriting career, Trumbo worked as a cub reporter and attended the University of Colorado for two years, contributing to several publications. He got his start in the industry working for Vogue magazine, and his first published novel, Eclipse, was written in the social realist style, drawing on his years in Grand Junction. He started writing for movies in 1937, quickly becoming one of Hollywood's highest paid writers.