This study investigates arbitrators' decisions in 557 suspension cases and reveals that, other things equal, male arbitrators were 74 per cent more likely to sustain the grievances of female grievants than male grievants. There was no evidence, however, that female arbitrators treat male and female grievants differently. A review of studies on gender effects in arbitration suggests a weak gender effect where male arbitrators are more lenient with female grievants than with male grievants.