Rodney Charles Ewing (born September 20, 1946) is an American mineralogist and materials scientist whose research is focused on the properties of nuclear materials. He is the Frank Stanton Professor in Nuclear Security at the Center for International Security and Cooperation, a Senior Fellow of the Freeman Spogli Institute for International Studies, a Senior Fellow of the Precourt Institute for Energy, an Affiliate of the Stanford Woods Institute for the Environment, and a Professor in the School of Earth, Energy and Environmental Sciences at Stanford University.