Environmental policy in the United States has always been characterized by high levels of political conflict. At the same time, however, policy makers have shown a capacity to learn from their own and others' experience. This article examines U.S. environmental policy since 1970 as a learning process and, more specifically, as an effort to develop three kinds of capacities for policy learning. The first decade and a half may be seen in terms of technical learning, characterized by a high degree of technical and legal proficiency, but also narrow problem definitions, institutional fragmentation, and adversarial relations among actors. In the 1980s, growing recognition of deficiencies in technical learning led to a search for new goals, strategies, and policy instruments, in what may be termed conceptual learning . By the early 1990s, policy makers also recognized a need for a new set of capacities at social learning, reflecting trends in European environmental policy, international interest in the concept of sustainability, and dissatisfaction with the U.S. experience. Social learning stresses communication and interaction among actors. Most industrial nations, including the United States, are working to develop and integrate capacities for all three kinds of learning. Efforts to integrate capacities for conceptual and social learning in the United States have had mixed success, however, because the institutional and legal framework for environmental policy still is founded on technical learning.