The world environmental movement has gained much strength in recent decades and has led many nations to focus on environmental education. We examine the extent to which this global movement has helped change national textbooks. We also consider the effects of national development, national policy on environmentalism, and the general expansion of postnational curricular emphases on human rights, student empowerment, internationalization, and social scientific perspectives. We analyze the content of 484 secondary school social studies textbooks from 65 countries, finding increased attention to the environment that parallels both world environmental crises and the closely related rise of world environmentalism. Our analyses suggest that the increasing prevalence of environmental topics in textbooks is influenced by broad global cultural and environmental change more than by national conditions.