This chapter introduces a strategic actor framework of environmental norm diffusion, which it uses to develop a theory of the diffusion of the norm of large marine protected areas. By incorporating domestic material interests into environmental norm diffusion, it builds norm diffusion theory to better explain why certain environmental norms gain global traction while others do not, as well as why there is considerable variation in how environmental norms are localized. The chapter also examines the interests of key stakeholder groups, including the state, extractive and non-extractive industry, environmental groups, and local communities. The framework foregrounds business influence to explain how governments attempt to reconcile new environmental norms with commercial interests. In some instances, business influence can lead to stronger protections, but more often tends to undermine conservation goals. This chapter analyses the potential and the limits of business influence over state conservation policy.