Our aim is to provide a comprehensive analysis of how processes of Europeanization affect Swedish civil society organizations (CSO) working with welfare policy and how they, strategically, make use of the European Union (EU) as a new political opportunity structure. Issues of Europeanization are neglected in much current research on Swedish CSOs. In a series of thematic studies - departing from theories on political opportunity structures, multi-level governance, institutional opening and social movements - we will investigate the dynamic interaction between EU institutions and collective actors. We will adopt a multi-method design and draw on comperative case studies as a key methodological approach. Two studies focus on structural conditions at EU level and pan-European CSOs activities. To investigate features, patterns and experiences of EU collaboration, we will also conduct a survey of Swedish CSOs working with welfare policies. In another study we will analyze the historical evolution of international/European cooperation among Swedish CSOs of this kind. Lastly, we will conduct an in-depth, comparative study of the multi-level strategies deployed by Swedish CSOs through investigations of strategically selected EU policy cases. The research group constitutes an interdisciplinary co-operation of researchers from the Faculty of Social Sciences, Lund University, and Södertörn University College and will provide key insight into the impact of the EU on Swedish CSOs.