Melissa S. Williams (born 1960) is an American academic who specialises in democratic theory and comparative political theory. She was the founding director of the University of Toronto's Centre for Ethics. As of 2018, she is a professor in the Department of Political Science at the University of Toronto. She gained an MESc from Bryn Mawr College, and AM and PhD degrees from Harvard University. Her doctoral advisers were Judith Shklar and Dennis F. Thompson. Her PhD thesis won the American Political Science Association's Leo Strauss Award.