This dissertation explores the relationship between immigration, diversity and minority nationalism. Through a study of Catalonia and its relationship with the Spanish state, the dissertation assesses how immigration and the growing social diversity that accompanies it, can challenge, undermine, or reinforce the political claims and objectives of minority nationalists, in particular, their goal of promoting a distinct and self-determining national community. It focuses on an effort by Catalan political and civil society leaders to construct a “national consensus” on immigration, the 2008 National Agreement on Immigration, which provided a 20-year plan for adapting Catalan government services and Catalan society to the pressures and demands of its increasingly diverse population, while at the same time providing mechanisms for the integration of newcomers into the Catalan language and national community. The analysis centres on the text of the National Agreement on Immigration as well as recent Catalan immigration plans and policy documents, in addition to the broader debate surrounding the National Agreement among Catalonia’s major political parties. The dissertation reveals that the National Agreement on Immigration represented both a significant re-framing of Catalan national identity and an attempt to expand the power and autonomy of the Catalan government by the various signatories to the accord. It concludes that the National Agreement represented an important component of a pivotal era in Catalan politics, one that has the potential to radically redefine the region’s relationship with both Spain and Europe, and in which questions surrounding immigration and diversity are increasingly intersecting with broader debates surrounding economic instability and the prospect of Catalan independence. / Graduate