Purpose This chapter analyzes the ways that individuals develop person- to-group ties. The chapter reviews the development and evidentiary basis of the theory of relational cohesion, the affect theory of social exchange, and the theory of social commitments. Methodology/approach We survey twenty-five years of published literature on these theories, and review unpublished theoretical tests and extensions that are currently in progress. Findings The research program has grown substantially over the past twenty-five years to encompass more varied and diverse phenomena. The findings indicate that structural interdependencies, repeated exchanges, and a sense of shared responsibility are key conditions for people to develop affective ties to groups, organizations, and even nation-states. Research limitations/implications The research implies that if people are engaged in joint tasks, they attribute positive or negative feelings from those tasks to their local groups (teams, departments) and/or to larger organizations (companies, communities). To date, empirical tests have focused on microlevel processes. Practical implications Our work has practical implications for how managers or supervisors organize tasks and work routines in a way to maximize group or organizational commitment. Social implications This research helps to understand problems of fragmentation that are faced by decentralized organizations and also how these can be overcome. Originality/value of the chapter The chapter represents the most complete and comprehensive review of the theory of relational cohesion, the affect theory of social exchange, and the theory of social commitments to date.