Can the media reduce intergroup prejudice and conflict? Despite the high stakes of this question, understanding of the mass media’s role in shaping prejudiced beliefs, norms, and behaviors is very limited. A yearlong field experiment in Rwanda tested the impact of a radio soap opera about two Rwandan communities in conflict, which featured messages about reducing intergroup prejudice, violence, and trauma. Compared to communities who listened to a control radio soap opera, listeners’ perceptions of social norms and their behaviors changed concerning some of the most critical issues for Rwanda’s post conflict society, namely intermarriage, open dissent, trust, empathy, cooperation and discussion of personal trauma. However, the radio program did little to influence listeners’ personal beliefs. Group discussion was a notable feature of the listening experience. Taken together, the results suggest that radio can communicate social norms and influence behaviors that contribute to intergroup tolerance and reconciliation.