In recent years, the prevalence of bullying among university students in Indonesia has continued to increase. The consequences of bullying have detrimental effects on the victims, highlighting the importance of finding ways to reduce bullying behavior. However, few studies have explored the factors that can mitigate this behavior among students. Therefore, this paper aims to analyze which determinants significantly affect the reduction of bullying behavior, with a particular focus on gender differences. This research utilizes the Theory of Planned Behavior (TPB) along with theories of parent-child relationships (PCR), teacher-student relationships (TSR), and peer relationships (PR) to explain bullying behavior. The study successfully collected data from 435 students in Riau, Indonesia. The results indicate that PCR and PR are key in enhancing students' attitudes towards bullying. As students' attitudes improve, bullying behavior can significantly decrease. This study successfully developed a research model to reduce bullying behavior. The findings suggest that fostering positive peer interactions and supportive parent-child dynamics are essential. Schools can apply these insights by promoting peer support systems and conflict resolution programs to reduce bullying. This study highlights the critical role of nurturing peer relationships within educational strategies to effectively address bullying behaviors.