This case study reveals the role of regional contextual variables in the geographical variability of anti-immigrant sentiment. It uses evidence from six regions in two different countries: Brussels, Flanders, and Wallonia in Belgium, and Andalusia, Catalonia, and Madrid in Spain. A comparative design, like the one proposed, permits isolating the role of demographic, economic, and political variables in the material, and cultural manifestations of anti-immigrant sentiment. Extant studies have emphasized differences between countries rather than differences within countries; we contribute to the literature by showing that differences within countries can be larger than between countries and provide a framework with which to understand these regional differences in anti- immigrant sentiment. In this case, we discuss how to measure contextual regional variables using mixed methods. Our analysis combines data from surveys, interviews, and socioeconomic and policy indicators with the goal of producing robust results, contributing to prevailing theories about inter-ethnic relations, and generating novel policy insights with the potential to strengthen multi-ethnic social cohesion.