<p dir="ltr">Confronting bias, or calling out clearly prejudiced statements or behaviors, signals anti-bias social norms to third-party observers. Across two studies (N = 1109), the current research extended this finding by examining whether confronting relatively subtle, ambiguous bias likewise signaled anti-bias social norms or resulted in confronter derogation. Participants aged 18-25 listened to a conversation among students, all of whom were men in an engineering class. One student either made a blatantly or more subtly biased comment about women’s engineering ability. Next, the comment was not confronted, was confronted by one other student, or was confronted by one other student and two other students affirmed the confrontation. Study 2 replicated Study 1 with a subtle comment that was phrased more ambiguously than in Study 1. For both blatant and subtle bias, confrontation strengthened participants’ perceptions of anti-bias descriptive and injunctive local norms compared to when the bias was not confronted. Others’ affirmation of the confrontation further boosted anti-bias norm perceptions relative to a non-affirmed confrontation. Moreover, results indicated that participants did not evaluate a confronter of subtle (vs blatant) bias negatively. Together, these findings indicate that confrontation effectively transforms norms in the face of blatant and relatively more subtle bias.</p>