Yokai Monsters (妖怪シリーズ) is a trilogy of Japanese horror/fantasy films written by Tetsuro Yoshida and released in the late 1960s. The films were produced by Daiei Film, and productions were largely influenced by Gamera and Daimajin franchises where Daimajin was also redeveloped from the Gamera franchise, and minor references among Gamera films and Daimajin and yōkai films to each other were inserted within respective franchises on various occasions.