Steven Gwon Sheng Louie (26 March 1949, Taishan, Guangdong, China) is a computational condensed-matter physicist. He is a professor of physics at the University of California, Berkeley and senior faculty scientist in the Materials Sciences Division at Lawrence Berkeley National Laboratory, where his research focuses on nanoscience. He is also scientific director of the Theory of Nanostructured Materials Facility at the Molecular Foundry.