Although blatant expressions of sexism in the American workforce appear on the decline, many researchers note that discrimination is not disappearing but is instead becoming more subtle and ambiguous. Drawing from Sue et al.’s construct of microaggressions, which examines manifestations of prejudice ranging from subtle to overt, the present research provides the first known empirical investigation of gender differences in third-party perceptions of microaggressions against women at work. Undergraduate women and men read vignettes describing interactions between male supervisors and female subordinates, which portrayed potentially discriminatory supervisor behavior, ranging in explicitness from subtle to blatant. Results indicate that although both men and women perceive differences in microaggression explicitness, women tend to detect greater discrimination than men, particularly when instances are subtle in nature. Both genders expect microaggressions to generate more negative work outcomes as explicitness increases. We discuss practical implications of our research, including the importance of raising awareness of workplace gender microaggressions, especially its most subtle forms, and of developing supporting programs to help observers of discrimination, who may be more likely to be women in cases of perceived microaggressions against women. Future research directions for addressing the broad range of discrimination facing working women today are also explored.