This paper provides evidence on the sources of differences in inequality in educational scores and their evolution over time in four European countries. Using Programme for International Student Assessment data from the 2000 and the 2006 waves, the paper shows that inequality decreased in Germany and Spain (two "decentralised" schooling systems), whilst it increased in France and Italy (two "centralised" systems). The decomposition exercise shows that educational inequality not only does reflect the background related inequality, but also schools' characteristics especially. These characteristics are responsible for the observed evolution over time of inequality.