Lay Nam Chang (章礼南, June 1, 1943 – December 8, 2020) was an American theoretical physicist. Over the course of his career, he published research on topics in particle physics, nuclear physics, general relativity, and quantum cosmology. In the mid-1970s, he also published pioneering work on the foundations of string theory. In 2003, he served as the founding dean of the College of Science at Virginia Polytechnic Institute and State University (“Virginia Tech”) and held that position until 2016.