Brian Randolph Greene is an American physicist. Greene was a physics professor at Cornell University from 1990–1995, and has been a professor at Columbia University since 1996 and chairman of the World Science Festival since co-founding it in 2008. Greene has worked on mirror symmetry, relating two different Calabi–Yau manifolds. He also described the flop transition, a mild form of topology change, showing that topology in string theory can change at the conifold point.

The World Science Festival is an annual science festival hosted by the World Science Foundation, a 501(c)(3) nonprofit organization based in New York City. There is also an Asia-Pacific event held in Brisbane, Australia.