Organizational scholars and institutional theorists have shown a great deal of interest in the concept of social capital. To a large extent, this interest has been fueled by accumulating evidence that social capital plays a vital role in the development of more cooperative, productive, and stable relationships within organizations and institutions. Recognizing these benefits, a major focus of recent theoretical efforts has been explicating the antecedents of social capital. Drawing on concepts from social identity theory and related theories of the self, this paper develops a framework for conceptualizing how individuals’ psychological identification with a collective enhances their willingness to engage in behaviors that contribute to the creation and maintenance of social capital. The paper reviews empirical evidence in favor of the framework and draws out some of its theoretical and applied implications.