Alvin Martin Weinberg (1915-2006) was an American nuclear physicist and administrator at Oak Ridge National Laboratory (ORNL) during and after the Manhattan Project.
Weinberg began working at the Metallurgical Laboratory at the University of Chicago in 1940. There, he worked closely with Enrico Fermi and other notable physcists to develop the world's first nuclear reactor. In 1942, Weinberg joined the Manhattan Project at the newly formed nuclear laboratory in Oak Ridge, Tennessee. There, Weinberg became the Director of the Physics Division at ORNL, where he helped develop different types of nuclear reactors.