Focusing on discretion by the police, criminal justice practitioners and the courts at different stages in the criminal justice process, this chapter explores whether their judgements and decisions contribute to the overrepresentation of those from black, minority ethnic and lower social status backgrounds in the criminal justice system. The chapter asks whether overrepresentation is due to alleged discrimination or reflects typical patterns of offending, and the policy implications. The structure of the chapter is first to present the most recent official data about overrepresentation taking note of recent trends. Contrasting this data with self-reported offending data shows that the overrepresentation of some ethnic groups in the criminal justice system is not a true picture of their actual offending. Second, I argue that an exclusive focus on ethnicity ignores social determinants such as socio-economic status and in any case the ethnic categories used to compare criminal justice outcomes are too crude. Third, I argue that residual discrimination by the police and the courts varies between and within jurisdictions and neighbourhoods, and by their ethnic and social class makeup. Fourth, because discretion is least visible and discrimination most likely at the police stage of criminal justice, police stop and searches are examined. Fifth, the conclusions examine police reform since the Lawrence Inquiry before broadening the discussion to wider structural issues of policy and reform