Takeo Yamaguchi (山口長男, Yamaguchi Takeo, born November 23, 1902, in Seoul, Korea, died April 23, 1983, in Tokyo, Japan) was an avant-garde Japanese painter of monochrome Art Informel works.

Yamaguchi studied Western painting at the Tokyo Art School. Upon graduation in 1927, he moved to Paris to study European painting. He developed his mature style during the mid-1950s, with a focus on flatness.^[1]

Yamaguchi's Yellow Eyes, painted in 1959, sold for US$948,500 at Sotheby's Contemporary Art Evening Sale in New York on May 18, 2017,^[2] which set a record for the highest price paid for the artist's work.^{[citation needed]}