This study aims to analyze the relationship between internal locus of control and peer social support on the career maturity of Vocational High School (SMK) students in Wonocolo District, Surabaya. This research uses a quantitative method. The population in this study consists of all SMK students in Wonocolo District, comprising 3 private SMK and 2 public SMK, with a total of 6,873 students. The research sample was taken using the Quota Random Sampling technique based on the Krejcie tabel, resulting in a sample size of 364 students. The data collection instrument uses scales that have been tested for validity and reliability. The measuring instruments used in this study are the Career Maturity Scale, the Internal Locus of Control Scale, and the Peer Social Support Scale. Data analysis was carried out using multiple linear regression tests to determine the influence of the independent variables on the dependent variable. The results showed that peer social support had a significant effect on the career maturity of students, meaning the hypothesis was accepted. Peer social support has a positive and significant relationship with the career maturity of students. The stronger the peer social support that students have, the higher the career maturity they achieve. On the other hand, internal locus of control did not show a significant relationship with students' career maturity, meaning the hypothesis was rejected. The belief of students in their internal control did not have a significant impact on career maturity.