Many countries are struggling to reconcile greater flexibility in school choice with the need to ensure quality, equity and coherence in their school systems. This report provides an international perspective on issues related to school choice, especially how certain aspects of school-choice policies may be associated with sorting students into different schools. A key question fuelling the school-choice debate is whether greater competition among schools results in more sorting of students by ability or socio-economic status. At the macro level, school segregation can deprive children of opportunities to learn, play and communicate with other children from different social, cultural and ethnic backgrounds, which can, in turn, threaten social cohesion. The report draws a comprehensive picture of school segregation, using a variety of indicators in order to account for the diversity of the processes by which students are allocated to schools.