The objective of this research is to determine the extent to which the effects of a business–nonprofit partnership (BNPP) go beyond those associated with their traditional roles of donor and beneficiary. Specifically, the study focuses on foundations as a distinct, fast-growing type of nonprofit, and evaluates the influence of engaging in partnerships with businesses on the not-for-profit organization’s (NPO) development of innovations, capacity building, visibility, scale of operations, funding, and mission accomplishment. We propose that stable relationships based on greater perceived value, communication, lower conflict, trust, and commitment improve innovation in nonprofits and give rise to a process of capacity building and better performance indicators. Empirical research is based on a survey of a representative sample of 325 Spanish foundations. Structural equation techniques served to analyze the data. The results confirm the positive effects of this type of BNPP.