Studies examining the direct effects of employee demographic differences on grievance filing have yielded mixed results. Moreover, little is known regarding the possible moderating effect that such differences might have on the link between workplace adversity and grievance filing. Using a sample of 866 blue-collar workers drawn from four unions, we examine the potential moderating effects of gender and race/ethnicity. Our findings suggest that while gender and ethnicity are not significantly associated with perceptions of workplace adversity, grievance filing in response to certain forms of adversity is amplified among women (as compared to men) and among African Americans and Hispanics (as compared to whites). The meaning and implications of these findings are discussed.