Eco-certification has risen in the last two decades as a prominent mode of private governance to promote sustainable production and consumption. However, the literature in this area has paid insufficient attention to the role of these initiatives in emerging economies, which have become leading producers and consumers of many commodities. This thesis focuses on China, a central player in global agri-food value chains, to examine the forces driving the diffusion of eco-certification in emerging markets. Drawing on new institutionalist theories, I argue that in the Chinese context, domestic state or quasi-state actors can provide critical support for the uptake of private governance, and interaction between transnational and domestic actors are central to this political process. This model is tested in China’s seafood, palm oil, and tea sectors. Using original qualitative and quantitative data including field interviews and firm surveys, I show that while Northern market agents initially introduced eco-certification programs in China, the information, services, and rewards provided by Chinese state or quasi-state actors have effectively motivated businesses to adopt the relevant standards. To increase their global impact, certification programs also need to proactively engage domestic stakeholders and devote resources on the ground. Despite these promising trends, evidence also suggests that certification has favored industrial, capital-intensive production, leaving many small businesses unaffected. The study offers new insights into the interaction among actors in private politics and the potential for sustainability governance in large emerging economies.