Environmental organizations in the United States are key actors in the process of social change. A rhetorical and historical perspective expands the understanding of different types of environmental organizations, and the actions that they follow. In the first section of this article, the role of language in constructing social movements is reviewed. This perspective is then applied in a second section to the environmental movement in the United States. Through a detailed reading of the philosophical and historical literature on environmental discourses, and an examination of the founding documents of leading environmental organizations, six environmental discourses are identified, and the incorporation of these discourses into environmental organizations is described. A close look at forty-four environmental organizations in the United States in a third section shows three distinct historical periods (Conservationist/Preservationist; Ecocentrist; and Political/Deep Ecology) through which the U.S. environmental movement has developed. The article concludes with some suggestions for further research.