The Mask of Dimitrios is a 1944 American film noir starring Sydney Greenstreet, Zachary Scott, Faye Emerson, Peter Lorre, and Victor Francen. Directed by Jean Negulesco, it was written by Frank Gruber, based on the 1939 novel of the same title written by Eric Ambler. Scott played the title role, of Dimitrios Makropoulos, in his film debut.

Sydney Hughes Greenstreet was a British and American actor. While he did not begin his career in films until the age of 61, he had a run of significant motion pictures in a Hollywood career lasting through the 1940s. He is best remembered for the three Warner Bros. films - The Maltese Falcon (1941), Casablanca (1942), and Passage to Marseille (1944) - with both Humphrey Bogart and Peter Lorre. He portrayed Nero Wolfe on radio during 1950 and 1951. He became an American citizen in 1925.