This chapter presents an overview of the two related disciplines of environmental ethics and environmental political theory, collectively termed “environmental thought.” The chapter begins with an illustrative example showing the differences between the two disciplines and then presents the historical roots of both disciplines and their subsequent emergence during the 1970s to 1990s. A closer look at each field follows. The section on environmental ethics focuses on anthropocentrism versus non-anthropocentrism and on pragmatism. The section on environmental political theory focuses on engagements with liberalism, justice, and democracy. The chapter wraps up with recent developments in environmental thought, including contributions and insights from African-American, indigenous, and feminist perspectives and a rethinking of the concept of nature. The chapter ends with a brief enumeration of salient questions and topics in environmental ethics and political theory going forward.