Teru "Tay" Hayashi (February 12, 1914 – December 18, 2003) was a Japanese-American cell biologist and physiologist known for his research on the biochemical mechanisms of muscle contraction. Hayashi was born in 1914 in Atlantic City, New Jersey, where he was raised by Japanese parents. In 1938, he received a physics degree from Ursinus College in Pennsylvania, followed by a Ph.D. in biology from the University of Missouri in 1943. At the University of Missouri, he studied under the supervision of Daniel Mazia.