This review adopts a critical perspective on geographical research on ethnic and racial segregation. It seeks to address four key questions. First, how can we conceptualize ethnic and racial segregation and what are the implications for geographical research? Second, how can we best measure ethnic and racial segregation? Questions about the politics of data collection, categorization and representation are addressed. Third, what does ethnic and racial segregation mean? The article examines the different forces underlying clustering and the way in which levels of segregation have become an indicator of migrant integration. Finally, the article reflects on how statistics and visual representations of minority ethnic segregation might be used in the political and policy sphere. It concludes that a critical perspective on ethnic and racial segregation requires us to acknowledge the gaps and silences in the data produced and the complexity, and often value-laden nature, of our interpretations.