This paper explores how social groups defend the ideal of European Union (EU) citizenship as proposed by the Commission against the backdrop of growing popular discontent with the process of European integration. More specifically, the paper probes the extent to which social groups can defend the mobility rights and associated benefits of EU citizens – that is to work, study and live in a member state other than their country of origin. It is anticipated that by seeking to defend these rights, social groups pose a potential challenge to the more established member state frameworks of citizenship. Drawing on critical discourse analysis of Commission documents and policy documents drawn up by such social groups, this paper draws attention to the conflicting impacts these groups are likely to have for national and EU citizenships today. It is suggested that the workings of these groups may, at the outset, appear as beneficial in generating awareness among citizens about their EU status. At the same time however, their existence may challenge the significance and future of EU citizenship, especially by contributing to mounting Eurosceptic and xenophobic responses from stayers – (formal) EU citizens who do not make use of their EU mobility rights – and the more nationally orientated social groups. These issues are likely to have important consequences for the Commission’s ideals – not only for EU citizenship but, by extension, for a political union that is “on the horizon” – and the (dis)integration process in Europe.