This paper compares the foreign citizens’ access to citizenship in the Iberian Peninsula. Portugal and Spain have been recurrently framed as an exceptional European immigration model. Moreover, the convergence thesis suggests that the policies of most industrialized nations will become increasingly identical, especially at the regional level. Drawing from a qualitative comparative analysis, this paper examines the extent to which the Portuguese and Spanish citizenship laws converged into a common and exceptional ‘Iberian model’ in the XXI century. The two countries’ citizenship regimes will be examined according to the tripartite framework proposed by Castles and Miller (1998), alongside their impact on the patterns of naturalization in the two countries. A range of hypotheses is tested to explain the divergences identified among the citizenship regimes of the two selected cases studies.