Kayo Yamaguchi (山口 華楊 Yamaguchi Kayō, 3 October 1899–16 March 1984) was a Japanese painter specializing in the nihonga style of watercolour painting. He was born in the Nakagyo ward of Kyoto。
Kayo studied under Nishimura Go'un. He supervised the 画塾晨鳥社. With a sketch-based painting style, he specialized in representations of animals. In 1981 he was awarded the Japanese order of culture.