New evidence is provided about the degree of social segregation in England's secondary schools, employing a cross-national perspective. Analysis is based on data for 27 industrialised countries from the 2000 and 2003 rounds of the Programme of International Student Assessment (PISA). We allow for sampling variation in the estimates. England is shown to be a middle-ranking country, as is the USA. High segregation countries include Austria, Belgium, Germany and Hungary. Low segregation countries include the four Nordic countries and Scotland. In explaining England's position, we argue that its segregation is mostly accounted for by unevenness in social background in the state school sector. Cross-country differences in segregation are associated with the prevalence of selective choice of pupils by schools. (Contains 13 notes, 4 figures, and 2 tables.)