Multi-stakeholder initiatives (MSIs)—private governance mechanisms involving firms, civil society organizations, and other actors deliberating to set rules, such as standards or codes of conduct, with which firms comply voluntarily—have become important tools for governing global business activities and the social and environmental consequences of these activities. Yet, this growth is paralleled with concerns about MSIs’ deliberative capacity, including the limited inclusion of some marginalized stakeholders, bias toward corporate interests, and, ultimately, ineffectiveness in their role as regulators. In this article, we conceptualize MSIs as deliberative systems to open the black box of the different elements that make up the MSI polity and better understand how their deliberative capacity hinges on problems in different elements. On the basis of this conceptualization, we examine how deliberative mini-publics—forums in which a randomly selected group of individuals from a particular population engage in learning and facilitated deliberations about a topic—can improve the deliberative capacity of MSIs.