Abstract: We study workers who are employed by a large US retailer, work in many store locations, and are paid based on performance. By means of a border-discontinuity analysis, we document that, compared to male workers in similar working conditions, female workers exert more effort and are terminated less often in response to a minimum wage increase. Based on an efficiency wage model, we compute an index of the welfare gain due to the minimum wage which, in our calibration, suggests that female workers benefit less than similarly-situated males from the minimum wage.  Consistent with an efficiency wage model, these gender differentials arise in times and locations where the outside option (market wage)  is much higher for men than women.