Two studies evaluated the lay belief that women feel particularly negatively about other women in the workplace and particularly in supervisory roles. The authors tested the general proposition, derived from social identity theory (Tajfel & Turner, 1979, 2004), that women, compared to men, may be more supportive of other women in positions of authority, whereas men would respond more favorably to other men than to women in positions of authority. Consistent with predictions, data from an online experiment (n = 259), in which the authors randomly assigned men and women to evaluate identical female (vs. male) supervisors in a masculine industry, and a correlational study in the workplace using a Knowledge Networks sample (n = 198) converged to demonstrate a pattern of gender in-group favoritism. Specifically, in Study 1, female participants (vs. male participants) rated the female supervisor as higher status, were more likely to believe that a female supervisor had attained her supervisory position because of high competence, and viewed the female supervisor as warmer. Study 2 results replicated this pattern. Female employees (vs. male employees) rated their female supervisors as higher status and practiced both in-role and extra-role behaviors more often when their supervisor was female. In both studies, male respondents had a tendency to rate male supervisors more favorably than female supervisors, whereas female respondents tended to rate female supervisors more favorably than male supervisors. Thus, across both studies, the authors found a pattern consistent with gender in-group favoritism and inconsistent with lay beliefs that women respond negatively to women in authority positions.