The project addresses the role of civil society organizations (CSOs) in democratization processes, bridging social science approaches to social movements and democracy. With a theoretical interest in the interactions between structure and agency, the project starts by revisiting the “transitology” approach to democratization and the political process approach to social movements, before moving towards more innovative approaches in both areas. From the theoretical point of view, a main innovation will be in addressing both structural preconditions as well as actors’ strategies, looking at the intersection of structure and agency. In an historical and comparative perspective, I aim to develop a description and an understanding of the conditions and effects of the participation of civil society organizations in the various stages of democratization processes. Different parts of the research will address different sub-questions linked to the broad question of CSOs’ participation in democratization processes: a) under which (external and internal) conditions and through which mechanisms do CSOs support democratization processes? b) Under which conditions and through which mechanisms do they play an important role in democratization processes? c) Under which conditions and through which mechanisms are they successful in triggering democratization processes? d) And, finally, what is the legacy of the participation of civil society during transitions to democracy on the quality of democracy during consolidation? The main empirical focus will be on recent democratization processes in EU member and associated states. The comparative research design will, however, also include selected comparisons with oppositional social movements in authoritarian regimes as well as democratization processes in other historical times and geopolitical regions. From an empirical point of view, a main innovation will lie in the development of mixed method strategies.