Present scholarship insufficiently addresses the linkages between Euroscepticism and supranational solidarity. On the one hand, scholars studying Euroscepticism argue that the lack of perceived benefits of the integration process explains EU citizens' opposition to their country membership in the union. However, this stream of literature does not inquire whether supranational social policies have the potential to change individuals’ perception of gains and losses related to European integration. On the other hand, the normative approach to European citizenship arguing for a transnational conception of justice and solidarity does not fully engage with the consequences of a social solidarity pillar in the EU. The SOCIALEU project builds on these two theoretical perspectives and investigates the role of a redistributive EU social policy in fostering citizen support for the Union. In particular, the project analyses the agenda-setting on social rights at the supranational level and subsequently inquires whether the provision of social benefits by EU institutions increases support for European integration and has the potential to turn populist party voters towards mainstream political parties. In doing so, the SOCIALEU project is the first theoretical and empirical undertaking that investigates the role that supranational social policy may have in changing people’s attitudes and voting behaviour in relation to the EU. I rely on the literature on welfare states’ role in strengthening national identity and social cohesion and argue that the provision of welfare goods at the EU level can strengthen support for the EU in general and among Eurosceptic citizens in particular. I employ an original research design that combines qualitative research in Brussels and survey experiments in France and Spain.