Multinational firms operate in multiple national jurisdictions, making them difficult for any one government to regulate. For this reason the firms themselves are often in charge of their own regulation, increasingly in conjunction with international organizations by way of public-private governance initiatives. Prior research has claimed that such initiatives are too weak to meaningfully change firms’ behavior. Can public-private governance initiatives help firms self-regulate, even if they lack strong monitoring or enforcement mechanisms? I take two steps toward answering this question. First, I introduce a new measure of firms’ performance on ESG (environmental, social, and governance) issues: the extent to which the firms issue public responses to claims of misconduct from civil society actors. Second, I argue that public-private governance initiatives allow firms to benefit from the legitimacy of their public partners, lowering the reputational cost of transparent response. Employing novel data on firm responses to human rights allegations from the Business and Human Rights Resource Center, I find that membership in the largest and most prominent initiative, the United Nations Global Compact, significantly increases firms’ propensity to respond transparently to stakeholder allegations. These results suggest a limited but important role for public-private initiatives in global governance.