Takeo Matsubara (松原武生, Takeo Matsubara, April 3, 1921 - December 15, 2014) was a Japanese physicist. Matsubara proposed a method of statistical mechanics related to Green's function (many-body theory), by applying quantum field theory techniques to statistical physics.He graduated from Osaka Imperial University, and worked as full professor in Hokkaido University, Kyoto University, and Okayama University of Science.