Are ethnic minorities treated differently from the Han Chinese in the Chinese courts? How does ethnic identity of judges affect sentencing severity? Using a newly and publicly available dataset of more than 120,000 drug offense cases in ethnically diverse provinces, we present the first analysis of ethnic bias in sentencing patterns in the Chinese local courts. We identify a degree of ethnic bias in the criminal justice system, but that the bias varies substantially across different jurisdictions. In Yunnan province, ethnic minority defendants receive longer sentences than Han defendants that have committed equivalent crimes, while bias is less prevalent in nearby provinces. Theoretically, this finding raises the possibility of ethnic minority concentration being a key determinant of sentencing outcomes. When ethnic minority groups hold a large share of the population in a region, and when that region witnesses social instability, minority defendants face disproportionately harsh sentences. Further analysis of county-level data from Yunnan province reveals evidence in favor of this hypothesis. We also test how the presence of lawyers might affect judge rulings. (Project and analysis completed with Rory Truex, Princeton University.)