JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. The shift away from school desegregation policies toward marketbased reforms necessitates a deeper understanding of the social and institutional forces driving contemporary school segregation. The author conceptualizes school segregation as a mode of monopolistic closure amid status competition, where racial/ethnic groups compete for school-based status and resources. He tests the theory by analyzing primary and secondary school segregation throughout the United States from 1993 to 2010. Findings support the hypotheses that segregation increases with the salience of race/ethnicity and the decentralization of school systems, which fuels differentiation and provides incentives and opportunities to monopolize schools. Parallel findings for blackwhite, Hispanic-white, and black-Hispanic segregation suggest that a core set of processes drives school segregation as a general phenomenon.School segregation has been central to our efforts to understand and address racial/ethnic educational inequalities for decades. Evidence indicates that desegregation policies in the 1960s-80s reduced racial inequality by improving blacks' academic and socioeconomic outcomes (Dawkins and