This thesis expands the scope of social stratification research in education to low- and middleincome contexts in sub-Saharan Africa (SSA). It examines how inequality of educational opportunity (IEO) changes as economies develop and educational systems expand, and assesses the drivers of intergenerational transmission of (dis)advantage. First, I explore whether educational expansion in the early 21st century led to equalization of children’s opportunities to attend and complete basic education. The study combines 153 Demographic and Health Surveys and Multiple Indicator Cluster Surveys from 40 countries in SSA capturing cohorts born between 1974 and 2003. Findings reveal that inequality by socioeconomic status (SES) in attending school declined, while inequality in completing six or more grades largely persisted. Second, I investigate to what extent national contextual factors explain variation in educational inequality between countries and cohorts. Findings show that material deprivation, demographic developments, school reforms, and colonial legacy are more predictive of IEO than economic development. Third, I assess to what extent inequality in reaching higher educational levels is explained by differences in cognitive ability development for the case study of Ethiopia. Drawing on longitudinal Young Lives survey data, findings show that while abilities explain a large part of the SES gap in educational attainment, inequality for this case study is larger among children with higher abilities, implying a loss of talent. Fourth, as secondary schools in most SSA countries are highly selective, I assess whether end-of-primary school examinations contribute to inequality in reaching post-primary education. Drawing on the longitudinal Mauritius Joint Child Health Project, findings reveal that unequal achievement in school-leaving examinations largely explains inequality, even for children with the same level of cognitive abilities and attending the same schools. This indicates that – next to developmental and financial issues – institutionally inbuilt qualification bottlenecks in this case study are co-drivers of educational inequality.