In this introduction to the special issue of Group Processes & Intergroup Relations on “Culture and Collective Action” we emphasize the importance of the special issue topic for the development of the field. Specifically, we highlight the globalization of collective action and the internationalization of the social-psychological study of collective action, both of which point to culture as a missing link for this field. We thus propose that the next step is to move toward a proper cultural psychology of collective action—a social psychology in which culture is an integral part. This special issue provides a first step toward such a broad and integrative psychological understanding of collective action, but comes with promises as well as problems. We discuss both the exciting synergies and some lessons to learn for the future, and conclude that a focus on culture will facilitate the development of the rich and fascinating field of the social psychology of collective action.