Yoko Mizuki (水木 洋子, Mizuki Yōko, 26 August 1910 – 8 April 2003) was a Japanese screenwriter. Born in Tokyo, she later graduated from Bunka Gakuin and began writing screenplays to support her family after her father died. Mizuki was active in the 1950s era of the Japanese studio system and is notable for her work with directors Tadashi Imai and Mikio Naruse. Her work had received several Best Screenplay Awards from Kinema Junpo and has been described in the book Women Screenwriters: An International Guide as "One of the most important and accomplished Japanese female screenwriters of all time".