Using detailed administrative records, we find that, on average, women receive lighter sentences in comparison with men along both extensive and intensive margins. Using parametric and semiparametric decomposition methods, roughly 30% of the gender differences in incarceration cannot be explained by the observed criminal characteristics of offense and offender. We also find evidence of considerable heterogeneity across judges in their treatment of female and male offenders. There is little evidence, however, that tastes for gender discrimination are driving the mean gender disparity or the variance in treatment between judges.