Bruce Allen (born May 11, 1959) is an American physicist and director of the Max Planck Institute for Gravitational Physics in Hannover Germany and leader of the Einstein@Home project for the LIGO Scientific Collaboration. He is also a physics professor at the University of Wisconsin–Milwaukee.
He has done research work on models of the very early universe (inflationary cosmology, cosmic strings). Allen currently leads a research group working on the detection of gravitational waves. In this role, he was one of the first scientists to become aware of the initial detection of GW150914 at LIGO, in September 2015. Allen's research work has been funded by the US National Science Foundation since 1987.