In the backdrop of highly constrained government and public sector finances in the U.S. as well as in Europe, private forms of regulation in natural resource and environmental policy have gained political and public salience at the nation-state and international levels. At the same time, the evidence has been mixed whether these new governance systems work or not and how they interact and cohere with existing public regulations. This panel, consisting of four papers, examines the motivation of the private sector and other stakeholders; explores the internal and external forces in the policy process that shape the participation in and the final form of private regulatory regimes; investigates the interactions of private regulation with existing regulatory regime; and evaluates the effectiveness of specific forms of private regulation. The first paper (Auld et al.) investigates private regulation in shaping global supply chains. In particular, the author explores the forest-certification choices of U.S. based multinational forest product companies over a 20 year period. The paper’s analysis considers the role played by activist pressure, public policy requirements, and internal firm structural and managerial factors in explaining different certification choices. In doing so, the paper draws lessons for the effectiveness of private regulation in the forest sector and beyond. The second paper (Hsueh) examines the effectiveness of a bilateral voluntary agreement negotiated between government and industry in reducing toxic chemical use in the U.S. The author investigates voluntary compliance by the pressure-treated wood industry to reduce its consumption of arsenic, a poisonous chemical that is ranked #1 on the EPA’s priority list of hazardous substances. Quantitative results show that the bilateral voluntary agreement led to substantial reductions in aggregate arsenic use. Systematic surveys elucidate the compliance-related decision-making processes involving firms, regulators, and NGO activists that led to the bilateral voluntary agreement. The third paper (Renckens) examines the various ways that private regulation interacts with existing public policy. Toward this regard, the paper analyzes how the European Union has attempted to regulate private regulatory initiatives in biofuels, organic agriculture, wild-capture fishing, and fair trade, and how the EU has integrated such private programs into public policy. The author draws lessons from the EU’s responses to private programs, with a focus on initial private program institutional designs, harmonization across private programs, and policy goals. The last paper (Davis) asks, does third party certification of sustainability predict changes in the management of common pool resources? The author uses time series analysis of individual fish stock to test the outcome of third-party certification by the Marine Stewardship Council in a case study of seven fisheries managed by the North Pacific Marine Stewardship Council. This paper provides insights into the effectiveness of third party certification as an alternative to traditional environmental policy tools, and informs policy options for governance of common pool resources.