This paper proposes an equilibrium concept for the classes of environments in which players can communicate with each other but cannot make binding agreements. The communication-proof equilibrium is intended to be regarded as an extension of both coalition- anThis paper proposes an equilibrium concept for the classes of environments in which players can communicate with each other but cannot make binding agreements. The communication-proof equilibrium is intended to be regarded as an extension of both coalition- and renegotiation-proof equilibria. Conceptual foundations for this particular definition are discussed as it is confronted with other definitions in these environments.[+][-]