The emerging social psychology of citizenship has made use of qualitative methods to explore people’s understandings of issues such as polity membership and its associated rights and responsibilities. Whereas there is a burgeoning tradition of work on conceptions of polity membership, as well as on civil and political citizenship, relatively little work has thus far focused on the concept of social citizenship—that aspect of citizenship which ensures that citizens have access to a basic income and standard of living. The present paper explores this in the context of debates over polity membership in relation to European Union (EU) immigration in the United Kingdom (UK). Data collected from posts to an Internet discussion forum are analyzed using an approach informed by discursive and rhetorical psychologies. The findings indicate a range of arguments in relation to social citizenship that were used by posters to suggest that EU immigration would have a negative effect on the UK, and that such arguments frequently involved particular constructions of groups (e.g., “immigrants,” “Romanians,” “Eastern Europeans”) as likely to claim welfare benefits, or as “low-skilled.” However, pro-immigration arguments could equally involve outgroup derogation, but in these arguments posters constructed images of subgroups of British citizens (e.g., “White working class Brits”) in order to suggest that immigration solved problems brought about due to the psychological deficiencies of these subgroups. It is suggested that this constitutes a previously underexplored dimension of immigration discourse, and that renewed attention to social citizenship and welfare can bring these complexities into focus.