In the world's richest countries, some children do worse at school than others because of circumstances beyond their control, such as where they were born, the language they speak or their parents' occupations. These children enter the education system at a disadvantage and can drop further behind if educational policies and practices reinforce, rather than reduce, the gap between them and their peers. These types of inequality are unjust. Not all children have an equal opportunity to reach their full potential, to pursue their interests and to develop their talents and skills. This has social and economic costs. This report focuses on educational inequalities in 41 of the world's richest countries, all of which are members of the Organisation for Economic Co-operation and Development (OECD) and/or the European Union (EU). Using the most recent data available, it examines inequalities across childhood -- from access to preschool to expectations of post-secondary education -- and explores in depth the relationships between educational inequality and factors such as parents' occupations, migration background, the child's gender and school characteristics. The key feature of the report is the league table, which summarizes the extent of educational inequalities at preschool, primary school and secondary school levels.