Merrill Brian Maple (born November 20, 1939) is an American physicist. He is a Distinguished Professor of Physics and holds the Bernd T. Matthias Chair in the Physics Department at the University of California, San Diego, and conducts research at the university's Center for Advanced Nanoscience. He has also served as the director of UCSD's Institute for Pure and Applied Physical Sciences (1995-2009) and its Center for Interface and Materials Science (1990-2010). His primary research interest is condensed matter physics, involving phenomena like magnetism and superconductivity. He has authored or co-authored more than 900 scientific publications and five patents in correlated electron physics, high pressure physics, nano physics, and surface science.