Collective action to protect the environment is increasingly moving into the focus of environmental psychology. Also policy makers are well-advised to consider the dynamics of collective environmental action as a vehicle to swift ecological transformations of societies. A sense of collective environmental agency (vs. treating citizens as reluctant consumers) is proposed to drive people supporting collective ecological transformations and engaging in personal and political action against large-scale environmental crises, such as climate change. The Global Environmental Psychology special section, “Responding to the Socio-Ecological Crisis: Collective Action and Activism”, presents nine empirical research articles that help to assess the antecedences and consequences of collective environmental agency. The present commentary discusses what the specific contributions of these papers are to better understand the emergence of collective environmental agency and what their implications are for future research in the field of social environmental psychology.