Alexander Rich (November 15, 1924 – April 27, 2015) was a biologist and biophysicist. He was the William Thompson Sedgwick Professor of Biophysics at MIT (since 1958) and Harvard Medical School. Dr. Rich earned both an A.B. (magna cum laude) and an M.D. (cum laude) from Harvard University. He was a post-doc of Linus Pauling along with James Watson. During this time he was a member of the RNA Tie Club, a social and discussion group which attacked the question of how DNA encodes genetics.