Can a government improve access to good schools for the poor when its middle-class supporters rely on educational advantage to maintain their own position in society? Recent advances in the study of comparative political economy of education have highlighted how inequalities created at school structure redistributive politics of higher education and skill formation systems. Yet, we still know little about the politics of redistribution of compulsory schooling – where everyone attends school, but the quality of the teaching and learning differs widely between schools. This book compares institutions which regulate school admissions – Student Sorting Institutions (SSIs) – and provides a political analysis of their reform trajectories in Western Europe. We gain an important tool for comparing school systems and a fresh perspective on partisan politics of education, where the divisions within parties matter as much as the rifts between them. Concretely, I propose that SSIs vary along two dimensions: can parents choose a school; and, can schools select students according to their performance? A comparative historical analysis of school reforms in Sweden, England, and France (1980-2010) shows that partisan governments’ policy preferences and reform behaviour follows the aim to improve educational opportunities for their constituents. I emphasise how political parties and their internal policy battles inform governments’ educational policies. The account provides insight into the politics of equality of educational opportunities in the present, with significant implications for the structure of the social cleavages and redistributive battles of the future.