In this chapter I examine contemporary theoretical frameworks that address four micro-level social comparison processes: social exchange, trust, justice, and legitimacy. I first review the basic elements of each process, as defined by scholars who work in their respective research traditions. I then describe theories that have emerged over the past decades that address how each process operates for individuals in social interactions, groups, and in greater society. I then review relevant empirical research that has furthered our understanding of each process. Finally, I discuss interrelations among exchange, trust, justice, and legitimacy and survey recent research that examines how these processes operate together during social interactions.