This study aims to explore influences of student-teacher relationships (STRs), child’s self-esteem (SE), prosocial behaviour (PB) on academic performance adjustment (APA) by applying structural equation modeling to 633 cases drawn from the 10th data collected for the PSKC by Korea Institute of Child Care and Education. The results of this study are as follows: First, the closeness in STRs had a significantly positive influence on SE and PB, and conflict in STRs had a negative influence on PB. However, conflict did not influence SE, and SE did not influence PB. Second, PB showed a partially mediated positive effect when closeness influenced APA. And PB had a fully mediated negative effect when conflict did. However, SE did not serve as a mediator for the influence of STRs on APA. These results suggest the need for the professional support programs to create and maintain intimate and positive STRs and to promote PB through empowering relationships, empathy, and social skills programs.