Spatial assimilation theory asserts that immigrants’ socioeconomic progress leads to residential adaptation and integration. This association has proven robust in USA and European urban areas through much of the twentieth century, but drastic change of ethnic and class compositions yet persistent (neighbourhood) inequality in the urban landscape urge us to reconsider the dynamic interaction between stability and change. In this study, we investigate to what extent education shapes residential mobility differently for young adults with varying ethnic and social origins. Focussing on Brussels, we use multinomial logistic regressions on linked longitudinal population-based censuses from 1991 and 2001 and register data for the period 2001–2006. Analyses show that dispersal away from poor inner-city neighbourhoods appears least likely for the offspring of poor low-educated non-Western households, regardless of their own educational attainment. While our approach roughly confirms traditional arguments of socio-spatial integration, it also reveals how educational success generates opportunities to escape poor neighbourhoods for some but not for others. With this, it points at the subtle ways in which factors and mechanisms in traditional spatial assimilation theory affect residential behaviour of young adults over their life course, at the intersection of specific locales, ethnic groups, social classes and generations.