Game Theory applied to relational contracts and institutions" This workshop aims to illustrate how game theory can contribute to better understand institutions and "relational contracts" (Gibbons, 2001). It will focus on repeated games that have been broadly used to explain the emergence of institutions. This theoretic framework highlights the role of commitment, reputation and self-enforcement in repeated relationships. Applications to guilds in the medieval Europe (Greif, Milgrom and Weingast 1994), to Maghribi traders (Greif, 1993), to franchising and to tacit collusion will be presented.