While the disparate legal treatment of immigrants in Western jurisdictions has been well documented in sociolegal scholarship, the potential legal inequality experienced by rural‐to‐urban migrants in China, who have become China's largest disadvantaged social group, has not garnered much attention. To fill the gap, this article empirically examines sentencing disparities related to the Hukou status of criminal offenders by employing quantitative data on criminal case processing in China. The results of our analysis reveal that rural‐to‐urban migrant defendants are more likely to be sentenced to prison than their urban counterparts. In addition, the penalty effect of being a rural‐to‐urban migrant is further magnified in jurisdictions with a larger concentration of migrants. Our findings suggest that discrimination against rural‐to‐urban migrants has become an emerging, significant form of legal inequality in China's criminal justice system, refracting and reinforcing the deep‐seated structural inequality associated with Hukou status in China. The research and policy implications of these findings are discussed.