This article examines the factors that influence the propensity of corporations to engage with NGOs. Drawing from resource dependency theory (RDT) and related theories of social networks and the resource-based view of the firm, the authors develop a series of hypotheses that draw from this conceptual foundation to predict a range of factors that influence firms to collaborate with NGOs. These factors include the level of commitment of the firm to CSR, the strategic fit between the firm’s and the NGO’s resources, the level of trust the firm has in NGOs, the frequency of contact with NGOs, prior level and perception of experience with NGOs, and the level of pressure exerted by NGOs. The authors report on results of a survey of the Top 500 firms in the Netherlands on their interactions with NGOs, finding general support for our hypotheses, and suggest that understanding the motives for firm–NGO interactions can teach us more about firms’ corporate social activities and the way such activities are shaped in the dynamic interplay between firms and their stakeholders. Our findings are relevant for future research on cross-sectoral interactions, for corporations considering future relationships with NGO cohorts, and for broader questions about the role of stakeholders and the role of business in society.