Sadao Yamanaka (山中 貞雄, Yamanaka Sadao, November 7, 1909 – September 17, 1938) was a Japanese film director and screenwriter who directed 26 films between 1932 and 1938. He was a contemporary of Yasujirō Ozu, Mikio Naruse and Kenji Mizoguchi and one of the primary figures in the development of the jidaigeki, or historical film. Yamanaka began his career in the Japanese film industry at the age of 20 as a writer and assistant director for the Makino company.