This ex-post facto research aims to identify the negative influence of peace of mind on students' aggressive behavior. Aggressive behavior of students has become a problem that has not been alleviated to the maximum and is increasingly complex. One model of education that seeks to build students' peace of mind is the peace education model. The use of this educational model can suppress the urge of students to show aggressive behavior. The research data was collected using the peace of mind scale (PoMS) and aggressive behavior scale (ABS). The research sample was taken using cluster random technique with a total of 1263 students coming from western part of Indonesia (East Java, the Special Region of Yogyakarta, and Lampung), the central part of Indonesia (West Nusa Tenggara and Central Sulawesi), and the eastern part of Indonesia (North Maluku). Data in this study were analyzed using simple linear regression. The results of the analysis of the study concluded that negative peace of mind has an effect of 62.9% on aggressive behavior committed by students. This study is recommended for future researchers to develop peaceful thinking training programs to reduce students' aggressive behavior.