Within the context of the Basque Country in Spain we examined how ethnic (Basque) and national (Spanish) identification relate to the evaluation of Spaniards, Basques, Andalusians and Catalans. On a sample of adolescent participants we tested a structural equation model which considered identity content (Basque separatism) as a mediator of the relationship between group identifications and group evaluations. While Spanish and Basque identification were associated with a positive evaluation of Spanish and Basque in-groups, respectively, the evaluation of out-groups that are relatively similar to the in-group were not affected by identification. In contrast, dissimilar out-groups tended to be evaluated more negatively by higher in-group identifiers. Basque separatism mediated the negative relationship between Basque identification and the evaluation of Spaniards and of Andalusians as a prototypically Spanish subgroup. It is concluded that identification relates differently to the evaluation of different out-groups, and that the ideological content of identity plays an important role in determining intergroup relations. Copyright © 2010 John Wiley & Sons, Ltd.