Iral B. Johns (1902-1987) was an American chemist.
An associate professor of chemistry at Iowa State University, Iral B. Johns joined the Manhattan Project in 1942 as a director of the plutonium proejct at the Ames, Iowa laboratory. Johns was immediately transferred to Los Alamos in 1943 to continue working on the Manhattan Project. He investigated methods of removing fission products from uranium. Eventually, he became the group leader of a chemistry group working with polonium. Johns was one of the official observers at the Trinity test site.