Janna J. Levin is an American theoretical cosmologist and a professor of physics and astronomy at Barnard College. She earned a Bachelor of Science in astronomy and physics with a concentration in philosophy at Barnard College in 1988 and a PhD in theoretical physics at the Massachusetts Institute of Technology in 1993. 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. She joined the faculty at Barnard College in January 2004 and is currently the Claire Tow Professor of Physics and Astronomy.