Recent years have seen the widespread rise of authoritarian leaders and populist politics around the world, a development of intense political concern. This special issue of the Annals explores the many and deep connections between this authoritarian and populist turn and environmental politics and governance, through a range of rich case studies that provide wide geographic, thematic, and theoretical coverage and perspectives. This introduction first summarizes major commonalities among many contemporary authoritarian and populist regimes and reviews debates regarding their relationships to neoliberalism, fascism, and more progressive forms of populism. It then reviews three major connections to environmental politics they all share as common contexts: roots in decades of neoliberal environmental governance, climate change and integrally related issues of energy development and agricultural change, and complex conflations of nation and nature. Next, it introduces the six sections in the special issue: (1) historical and comparative perspectives (two articles); (2) extractivism, populism, and authoritarianism (six articles); (3) the environment and its governance as a political proxy or arena for questions of security and citizenship (seven articles); (4) racialization and environmental politics (five articles); (5) politics of environmental science and knowledge (six articles); and (6) progressive alternatives (five articles). It concludes with the suggestion that environmental issues, movements, and politics can and must be central to resistance against authoritarian and reactionary populist politics and to visions of progressive alternatives to them. Key Words: authoritarianism, environmental governance, environmental politics, populism.