Katsuhiro Yamaguchi (山口勝弘, Yamaguchi Katsuhiro; 22 April 1928—2 May 2018) was a Japanese artist and art theorist based in Tokyo and Yokohama. Through his collaborations, writings, and teaching, he promoted an interdisciplinary avant-garde in postwar Japan that served as the foundation for the emergence of Japanese media art in the early 1980s, a field in which he remained active until his death. He represented Japan at the 1968 Venice Biennale and the 1975 Bienal de São Paulo, and served as producer for the Mitsui Pavilion at Expo '70 in Osaka.