Peer rejection refers to the extent to which a person is disliked by their peers. Inhibitory control, is one of key components of executive functions, involving being able to control one’s attention, behavior, thoughts, and/or emotions to override a strong internal predisposition or external lure, and instead do what’s more appropriate or needed. Inhibitory control is a predictor of peer rejection. However, little is known about the mediating mechanisms underlying this relation. According to a heuristic model of social competence proposed by Yeates et al. (2007) and a model in Hay et al.’s (2004) review, children with poor EF are more likely to be socially maladjusted, including being more rejected, because they have specific impairments in social cognition (e.g., theory of mind) and display greater negative social behaviors (e.g., aggression). When applied specifically to inhibitory control, this model suggests that the higher rates of aggression may explain why deficit in inhibitory control is associated with peer rejection. There are physical and relational forms in aggression. The existing studies have well established the negative association between inhibitory control and physical aggression, but the association between inhibitory control and relational aggression is still not clear. Some researchers hold the view that consistent with physical aggression, inhibitory control also negatively predicts relational aggression; whereas others argue that inhibitory control is not related to relational aggression. Moreover, previous researches demonstrated that physical and relational aggression show unique associations with peer rejection. The current study was to explore the mediating roles of physical and relational aggression in the association between inhibitory control and peer rejection, and to compare difference of the mediating effects of physical aggression and relational aggression. One thousand five hundred and eighty-nine adolescents of grade 9 (mean age 15.22 ± 0.36 years old) from 91 classes of 8 junior high schools, were investigated. The inhibition subscale from Behavior Rating Inventory of Executive Function was administrated to measure inhibitory control through parent-report. Physical aggression and relational aggression were assessed through peer rating, and peer rejection was obtained through peer nomination. All of the measures showed good reliability. The results revealed that (1) significant correlations existed between adolescents’ inhibitory control, physical aggression, relational aggression, peer acceptance and peer rejection; (2) both physical and relational aggression mediated the associations between inhibitory control and peer rejection; and the mediating effect of physical aggression was stronger than that of relational aggression. The present study extends previous studies in two aspects. Firstly, this study provides insight into one possible mechanism underlying the relation between inhibitory control and peer rejection. That is, adolescents’ inhibitory control had indirect effect to peer rejection through physical and relational aggression, supporting previous models proposed by Yeates et al. (2007) and Hay et al.’s (2004). Furthermore, we found a stronger mediating effect of physical aggression than that of relational aggression. Specifically, inhibitory control better predicted physical aggression than relational aggression. One possible explanation is that relational aggression is of highly socially complex nature and relied heavily on the social network. These results emphasize on the important role of social behaviors in association between inhibitory control and peer functioning. Future studies will need to continue to examine other potential mechanisms by longitudinal design.