This article examines the dynamics of the relationship between residential and school segregation in Barcelona. The analysis explores which educational and non-educational drivers foster the school segregation of foreign students between the city’s neighbourhoods. The article also analyses to what extent the particularities of Barcelona’s admissions policy, which combines catchment areas with high levels of school choice, generate specific mechanisms of contextually bound school segregation within the local education market. The results confirm that residential segregation and educational segregation are two interrelated phenomena in Barcelona. In addition, the supply of publicly subsidised private schooling in the neighbourhoods is a main factor driving both educational segregation and isolation, especially in those neighbourhoods with a high concentration of foreign pupils. Based on the results, the article elaborates on the challenges for local education policymaking to address the dynamics of school segregation in urban spaces.