Leo Mittler (18 December 1893 – 16 May 1958) was an Austrian playwright, screenwriter and film director. Mittler was born in Vienna to a Jewish family. Following the Nazi rise to power in 1933, Mittler spent many years in exile in several countries, including Britain and France, before settling in the United States during the Second World War. Mittler's career as a director had all but ended in the mid-1930s, after making the Stanley Lupino musical comedy Cheer Up (1936), but he worked occasionally as a screenwriter.

Mittler wrote the original story of the MGM pro-Soviet film Song of Russia (1944) which was later investigated by the House Un-American Activities Committee for its alleged communist sympathies. Mittler returned to Germany post-war, dying there in 1958. Before his death, he worked in German theatre and television.