Since the Supreme Court's 1954 Brown v. Board of Education decision, researchers and policy makers have paid close attention to trends in school segregation. Here we review the evidence regarding trends and consequences of both racial and economic school segregation sinceBrown. The evidence suggests that the most significant declines in black-white school segregation occurred in the late 1960s and early 1970s. There is disagreement about the direction of more recent trends in racial segregation, largely driven by how one defines and measures segregation. Depending on the definition used, segregation has either increased substantially or changed little, although there are important differences in the trends across regions, racial groups, and institutional levels. Limited evidence on school economic segregation makes documenting trends difficult, but students appear to be more segregated by income across schools and districts today than in 1990. We also discuss the role of desegregation litigation, demographic changes, and residential segregation in shaping trends in both racial and economic segregation. We develop a general conceptual model of how and why school segregation might affect students and review the relatively thin body of empirical evidence that explicitly assesses the consequences of school segregation. We conclude with a discussion of aspects of school segregation on which further research is needed.