Brockway McMillan (March 30, 1915 – December 3, 2016) was an American government official and scientist, who served as the eighth Under Secretary of the Air Force and the second Director of the National Reconnaissance Office. McMillan served as the President of the Society for Industrial and Applied Mathematics (SIAM) 1959-1960. In 1942, while at Princeton University, McMillan married (1915–2008) who had a PhD in mathematics from Radcliffe College in Cambridge, Boston, in 1938. He died on December 3, 2016 at his home in Sedgwick, Maine at the age of 101.