Cross-sector partnerships are an increasingly popular mode of organizing to address intractable social problems, yet theory and research have virtually ignored university involvement in such activity. This article attempts to ascertain the reasons universities join networks of other social actors to support a common cause. Theories on the formation of interorganizational relationships have tended to emphasize efficiency, resource dependence, legitimacy, leverage, and mutuality as central motivators or concerns. These only partially describe motivations for cross-sector social partnerships, however, which often focus on the issue or problem itself as an organizing principle. Evidence from an empirical study of the LEAD (Leadership Education and Development) Program in Business, a pipeline development initiative to introduce underrepresented students to business education and careers in business, supports this problem domain-based view of cross-sector social partnering. Implications for theory and practice are discussed. (Contains 1 endnote.)