Tamio Kageyama (景山 民夫, Kageyama Tamio, March 20, 1947 - January 27, 1998) was a Japanese novelist and broadcast writer. Another pen name as a broadcast writer is Tetsutarō Ōoka (大岡 鉄太郎).

He won the 99th Naoki Prize in 1988 for his novel Coo: Tooi Umi Kara Kita Coo, later adapted into an animated film. Kageyama also contributed to the films Sakana kara daiokishin!! (1992), Saraba itoshiki hito yo (1987), and Hoshikuzu kodai no densetsu (1985).