Masaki Tsuji (辻 真先, Tsuji Masaki, born March 23, 1932 in Nagoya) is a Japanese scenario writer of TV series (including many anime works) and films as well as mystery fiction novels. Tsuji was most active in the business from the 1960s through the 1980s, and worked as a script writer on many popular anime television series for Mushi Production, Toei Animation, and Tokyo Movie Shinsha. He is well known for his association with the animated adaptations of the works of Osamu Tezuka and Go Nagai.