This paper presents an approach to the study of European Iron Age ethnicity, a core topic for several decades which has begun to lose interest in the last years. A review of some of the uncertainties involved in the archaeology of ethnicity, focused on several key issues, is proposed. Moreover, some relevant topics that are usually undermined are suggested in order to address new challenges in the discipline: the introduction of political identity as a major focus of study, the reassessment of the etic perspective as an inner part of processes of collective differentiation, or the need for a holistic approach to join and combine different forms of expression. Finally, these approaches will be explored in a case study based on the northwest of the Iberian peninsula. This region has been chosen because of the feasibility of combining the results of different studies about social and political organizsation with relevant textual evidence to extract information about their ethnic dynamics.