Social exchanges are an essential part of our everyday lives, including face-to-face interpersonal relations, digitally mediated interpersonal communications, engagements with groups or associations offline or online, and interactions with the institutions in which our lives are embedded. In the first half of this chapter, we consider social behavior as exchange, including the links between social exchange and social structure, power dynamics, and how different types of exchange are associated with commitment, social cohesion, fairness, and collective action. In the second half, we discuss the social exchange approach at the micro (i.e., interpersonal), meso (e.g., groups and organizations), and macro (institutional) levels of analysis. We address both non-economic and economic aspects of exchange at each level, across a variety of substantive applications. We conclude with comments on new developments and future directions for social exchange research, including in key areas such as healthcare and technology-mediated exchange platforms.