Leonidas (Leon) Alaoglu was a Canadian-American mathematician and operations researcher. During his six-year stint as a mathematician from 1938 to 1944, Alaoglu studied several topics, including topology, number theory, and the geometry of polyhedra. His best known result, which he proved during this period, was Alaoglu's theorem on the weak-star compactness of the closed unit ball in the dual of a normed space. After 1944, he left academia for the world of operations research.