Cyril Smith (1903-1992) was a British metallurgist. He was married to the historian Alice Kimball Smith.
In 1942 he was called into service to work on the War Metallurgy Committee in Washington, DC. He was transferred to Los Alamos to continue work on the Manhattan Project, directing the preparation of fissionable metal for the atomic bomb and other materials for nuclear experiments.
He was present at the Trinity test in July 1945 and later wrote: "At the instant after the shot, my reactions were compounded of relief that 'it worked'; consciousness of extreme silence, and a momentary question as to whether we had done more than we intended."
After the war, Smith founded the Institute for the Study of Metals at the University of Chicago. He was one of the original nine members of the United States Atomic Energy Commission’s General Advisory Committee, and a member of the President’s Science Advisory Committee.