Rudolf Klein-Rogge (November 24 1888–April 30 1955) was a German stage and film actor of the 1920s and 30s. He is best known for his roles as the mad scientist C. A. Rotwang in Fritz Lang's film Metropolis, and as the title character in Lang's Dr. Mabuse series.

Frequently worked with director Fritz Lang, for whom he starred in ten films.

Was once married to Thea von Harbou, who was Fritz Lang's wife and collaborator until Lang fled Nazi Germany. (Harbou, a Nazi sympathizer, stayed behind.)