Yasutarō Yagi (八木保太郎, Yagi Yasutarō) (3 February 1903 – 8 September 1987) was a Japanese screenwriter, mostly famous for his adaptations of literary works for the director Tomu Uchida in the 1930s, such as Jinsei gekijō and Kagirinaki zenshin,[1] and for his collaborations with leftist filmmakers such as Kaneto Shindo and Tadashi Imai in the postwar period.

He served as president of the Japan Screenwriters Guild.