In 1993, McCabe and Treviño published a seminal paper in which they proposed that honor codes reduced academic misconduct among college students. I review the research on honor codes that has emerged in the last 30 years. The extant body of literature demonstrates the efficacy of honor codes in creating and maintaining a culture of academic honesty and integrity in institutions of higher education. Although the findings are nuanced, honor codes appear to work by educating students about academic integrity and holding them accountable through social norms, expectations, attitudes, reminders, and clear policies for addressing academic misconduct. Directions for future research are proposed.