This article tackles the issue of social citizenship in Europe, beyond its legal and political defini-tion, as the result of social mechanisms and practices, and it assumes the cosmopolitan perspective as a conceptual tool for the interpretation of changes in its principles and structure as related to Europeaniza-tion and globalisation. It starts from the heuristic value of the concept, grounded in modern industrial so-cieties and built on its institutions and forms of social solidarity. Then it draws on the debate about the challenges of the welfare state and capitalism's transformations, as well as on the impact on social citizen-ship of the European integration process. It proposes cosmopolitanism as a lens for catching cosmopolitan ideas, narratives and values that contribute to creating new practices of solidarity and mutual recognition, which are the basis for the construction of new kinds of sustainable social citizenship in Europe. The Euro-pean social forum of 2012 has been considered a significant case study for an empirical exploration of the cosmopolitan imagination as a factual process. A cosmopolitan epistemology takes shape, based on the values of commons and global public goods. Meanings, actions and practices enhanced by social actors, building solidarity in diversity and following global-local logics, show forms of recognition of otherness and of sharing global responsibilities representing a tendency towards a new conception of European social citizenship. Social rights and recognition beyond territorial boundaries are at the core of the construction of a cosmopolitan citizenship in Europe.