The present study identified the personal and familial variables related to relational victimization of girls and functioning mechanisms of these variables. For this, maternal rejective parenting was set as a familial variable, and trait anger and gender role traits were set as personal variables. Moreover, the mediating roles of trait anger, agency, unmitigated agency, communion, and unmitigated communion in the relationship between maternal rejective parenting and girls’ relational victimization were examined through structural equation modeling. A total of 815 elementary school girls in 5th and 6th grades sampled from fourteen elementary schools participated in this study. The results indicated that although maternal rejective parenting had significant direct effects on all the mediating variables included in the model, unmitigated communion was the only mediator showing a significant mediating effect. That is, maternal rejective parenting made girls vulnerable to relational victimization by developing unmitigated communion. Based on these findings, effective prevention/intervention strategies for reducing girls’ victimization of relational aggression were discussed.