One of non-cognitive factors which has not been optimally explored in supporting academic achievement was self-disclosure. To overcome that problem, the purpose of this study is to examine the relation between students' self-disclosure to their parents and the mathematics score achievement in the Computer-Based National Exam (UNBK) program. This study used descriptive analysis and correlation analysis as a research method. The study used the mathematics score of Junior High School (SMP) and Islamic Junior High School (MTs) students in 2018 UNBK in DKI Jakarta and DI Yogyakarta provinces as samples. The study shows that (1) there is a positive relation between students' self-disclosure to their parents and mathematics score achievement, and (2) students with low self-disclosure had a greater risk of achieving mathematics scores in the low category. The findings of this study are expected to extend the contribution of self-disclosure in enhancing academic achievement, and the development of a self-disclosure instrument for UNBK questionnaire. [For the complete proceedings, see ED608557.]