There is robust evidence that preschool participation yields beneficial effects on cognitive, social and emotional development, and academic achievements later on. These effects are particularly important for children in poverty and at risk of social exclusion. Research shows that quality of educational provision matters, yet there is inconsistency in the findings on what aspects of quality make a difference for learning at an early age. More in-depth qualitative research is needed to understand the preschool learning experiences of children living in deprived situations and to unravel when the educational setting levels the playing field rather than reproduces social inequality. Full-day preschool in the Flemish Community of Belgium is universal from 2,5 years on. Children from diverse socio-economic and ethnic groups share the same classrooms. Therefore it offers a unique research context. We will conduct a multiple case study in 4 very diverse cases. In each case, a general assessment of the quality will be done and in-depth video-observations of two children, in interaction with teachers, peers and parents, will document their learning experiences during their first year in preschool. The contextualized analysis of the data will allow gaining more insight in the black box of children's learning experiences where quality and learning outcomes are mediated.