Ecological modernization theory posits that social movements play a central role in the environmental transformation of contemporary society. How they do so has received limited scholarly attention. This article seeks to reduce this thesis to a number of propositions which are then examined in light of the experience of the pulp and paper industry in the 1980s and 1990s. Drawing on field research and interviews in Southeast Asia, Australia and the United States, as well as available data, the study finds that social movements were instrumental in the environmental transformation of the pulp industry, with important differences between North and South. It concludes with a call for more nuanced studies of the influence of social movements on different sectors and countries, especially in newly industrializing countries where more tenuous and dependent forms of ecological modernization may be emerging.