This study examines the joint impact of neighborhood structure and ethnic density on the educational attainment of the second generation. Using second-generation samples and a majority reference sample from the Belgian Census, multi-level analysis yields the expected positive effects of neighborhood stability and quality and ethnic density on second-generation school completion. Reflecting the ethnic stratification of the Belgian housing market, majority residential concentration tends to coincide with high neighborhood stability and quality and high completion rates, whereas Moroccan concentrations overlap with low neighborhood quality, and low completion rates. For the Turkish and Italian second generation, neighborhood structure moderates ethnic density effects on school completion, in line with segmented assimilation. Our findings suggest distinct Moroccan, Turkish and Italian incorporation modes which reflect differential access to, and investments in ethnic versus mainstream social networks. [ABSTRACT FROM AUTHOR]