In this article, we review the theory of ecologically unequal exchange and its relevance for global environmental injustice. According to this theory, global political–economic factors, especially the structure of international trade, shape the unequal distribution of environmental harms and human development; wealthier and more powerful Global North nations have disproportionate access to both natural resources and sink capacity for waste in Global South nations. We discuss how the theory has roots in multiple perspectives on development, world‐systems analysis, environmental sociology, and ecological economics. We detail research that tests hypotheses derived from ecological unequal exchange theory on several environmental harms, including deforestation, greenhouse gas emissions, biodiversity loss, and water pollution as well as related human well‐being outcomes. We also discuss research on social forces that counter the harmful impacts of ecologically unequal exchange, including institutions, organizations, and environmental justice movements. We suggest that ecologically unequal exchange theory provides an important global political–economic approach for research in environmental sociology and other environmental social sciences as well as for sustainability studies more broadly.