Robert Marion Sayre (August 18, 1924 – March 31, 2016) was a United States State Department official and ambassador to Brazil, Panama and Uruguay. A career foreign service officer specializing in Latin American affairs, Sayre served as the United States Ambassador to Uruguay from 1968 to 1969, Ambassador to Panama from 1969 to 1974, and Ambassador to Brazil from 1978 to 1981. He also held the position of Inspector General of the U.S. State Department from 1974 to 1978.