This study explores the impact of self-discipline on unethical behaviors in college students’online activities, the mediating role of integrity, and the moderating effect of reactance. Data from 434valid questionnaires were analyzed using mediation and moderated mediation models. The findings revealthat: (1) There is a significant negative correlation between self-discipline and unethical online behaviorsamong college students; (2) Integrity partially mediates the relationship between self-discipline and thesebehaviors; (3) Reactance moderates the mediated effect of self-discipline on unethical behaviors throughintegrity, with a more pronounced mediated effect at higher levels of reactance. The results confirm thedirect impact of self-discipline on unethical online behaviors and its indirect impact through integrity.Additionally, the moderating role of reactance highlights the importance of individual differences in therelationship between self-discipline and online ethical misconduct. This research provides theoreticalinsights and practical implications for reducing unethical online behaviors among college students.