Climate change and degradation of the environment are global problems associated with many other challenges (e.g., population increases, reduction of glaciers, and loss of critical habitats). Psychological science can play a critical role in addressing these problems by fostering a sustainable environment. Multiple strategies for fostering a sustainable environment could draw from the diversity of topics and areas of specialization within psychology. Psychological research on fostering environmentally sustainable behaviors is rather well developed, as illustrated by interventions focusing on education of the public, message framing, feedback, decision making, the media, incentives and disincentives, and social marketing. Other sciences and professions as well as religion and ethics are actively involved in fostering a sustainable environment. Psychology ought to be more involved directly, systematically, and visibly to draw on our current knowledge and to have palpable impact. We would serve the world very well and in the process our discipline and profession.