George William Whitehead, Jr. (August 2, 1918 – April 12, 2004) was an American professor of mathematics at the Massachusetts Institute of Technology, a member of the United States National Academy of Sciences, and a Fellow of the American Academy of Arts and Sciences. He is known for his work on algebraic topology. He invented the J-homomorphism, and was among the first to systematically calculate the homotopy groups of spheres. He is also central to the study of Stable homotopy theory, in particular making concrete the connections between Spectra and Generalized homology/cohomology theories.