The importance of peer relationships among teenagers makes them form peer groups. Peer groups are children or adolescents with the same age or maturity level. Peer interactions of the same age play a unique role among adolescents. The purpose of this study is to see the effect of peer groups on the self-esteem of Lampung and Java students. The research method used ex-post facto research with 40 research students of Grade XI SMK Negeri Talangpadang Lampung Lesson Year 2016/2017 consisting of 20 students of Lampung tribe and 20 students of Java tribe. The instrument used is a questionnaire of peer groups and self-esteem questionnaires. Data analysis technique used is a parametric statistic with regression analysis. The results showed that there is a significant influence among peer groups on student self-esteem. Peer groups contributed 34.9% of students' self-esteem, while the remaining 65.1% were influenced by other factors.