Janna J. Levin is an American theoretical cosmologist. She earned a PhD in theoretical physics at the Massachusetts Institute of Technology in 1993, and a Bachelor of Science in astronomy and physics with a concentration in philosophy at Barnard College in 1988. Much of her work deals with looking for evidence to support the proposal that our universe might be finite in size due to its having a nontrivial topology. Other work includes black holes and chaos theory. Since January 2004, she has been a professor of astronomy and physics at Barnard College of Columbia University.