Diego Gambetta (Italian pronunciation: [ˈdjеːɡo ɡamˈbetta]; born 1952) is an Italian-born social scientist. He is a professor of social theory at the European University Institute in Florence, a Carlo Alberto Chair at the Collegio Carlo Alberto in Turin, and an official fellow at Nuffield College, University of Oxford. He is well known for his vivid and unconventional applications of economic theory and a rational choice theory approach to understanding a variety of social phenomena. He has made important analytical contributions to the concept of trust by using game theory and signalling theory.