End-of-the-semester teaching evaluations hold consequential weight in professors’ career outcomes, which can be problematic if these evaluations are affected by gender bias. This research sought to examine gender bias in evaluations of professors through two experimental studies (via a 15-minute online lecture and a university-sanctioned online course), offering two ecologically valid manipulations of professor gender. Student gender and field of study were examined as moderators of this gender bias, as effects may be more pronounced among male raters compared to female raters, or among raters in majors that underrepresent women compared to raters in other majors. Findings revealed an effect of professor’s gender in the opposite direction: On average, students rated female professors more positively than they did male professors. Student gender and field of study did not affect professor ratings, nor did they moderate the effect of professor gender.