Rudolf Wlassak (27 March 1865, Brno - 10 March 1930, Vienna) was an Austrian physiologist and neurologist. He was a pioneer in the hospital treatment of alcoholism.
He was born in Brno, Austrian Empire (now Czech Republic). He studied medicine at the University of Leipzig, and in 1893 qualified as a lecturer in Zürich. After time spent in Rome and Florence, he started a neurological practice in Vienna Neustadt (1919), and worked with Emil Redlich at the Maria-Theresien-Schlössel Hospital in Vienna. In 1922 he became director of a sanatorium for alcoholics called "Am Steinhof".
He conducted research on the structure of cerebellum and on the physiology of the senses and spatial perception.
He died in Vienna.