This study examined the influences of maternal and paternal psychological control and children's rejection sensitivity on relational aggression in elementary school students, and investigated whether children's rejection sensitivity mediated the relation of parental psychological control and relational aggression. Methods: The participants of this study were 596 fifth to sixth graders from seven elementary schools located in Seoul, Incheon, and Gyeonggi province. To measure the research variables, the Peer Conflict Scale (Marsee, Kimonis, & Frick, 2004), the Psychological Control Scale (Barber, 1996) and the Children's Rejection Sensitivity Questionnaire (Downey, Lebolt, Rincón, & Freitas, 1998) were used. The data were analyzed by means of descriptive statistics and t-tests. Also, structure equation model (SEM) were used to examine the mediating role of rejection sensitivity. Results: The results of this study were as follows. First, the level of paternal psychological control increased the level of children's relational aggression whereas the level of maternal psychological control had no significant effect on it. In addition, the level of rejection sensitivity had a significant positive influence on the level of relational aggression. These tendencies were observed on both boys and girls. Second, only for boys, rejection sensitivity in upper elementary school students partially mediated the relation between paternal psychological control and relational aggression. Also, for both boys and girls, rejection sensitivity completely mediated the relation between maternal psychological control and relational aggression. Conclusion: In conclusion, the higher the level of paternal psychological control, the higher the level of children's rejection sensitivity, and subsequently the higher the level of their relational aggression