Walter Ruttmann (28 December 1887 – 15 July 1941) was a German film director and along with Hans Richter and Viking Eggeling was an early German practitioner of experimental film.
Ruttmann was born in Frankfurt am Main; he studied architecture and painting and worked as a graphic designer. His film career began in the early 1920s. His first abstract short films, "Opus I" (1921) and "Opus II" (1923), were experiments with new forms of film expression, and the influence of these early abstract films can be seen in the early work of Oskar Fischinger. Ruttmann and his colleagues of the avant garde movement enriched the language of film as a medium with new form techniques.
Ruttmann was a prominent exponent of both avant-garde art and music. His early abstractions played at the 1929 Baden-Baden Festival to international acclaim despite their being almost eight years old. Together with Erwin Piscator, he worked on the experimental film Melodie der Welt (1929), though he is best remembered for Berlin: Die Sinfonie der Großstadt (Berlin: Symphony of a Great City, 1927).
During the Nazi period he worked as an assistant to director Leni Riefenstahl on Triumph of the Will (1935). He died in Berlin.