When children are “left behind”, aggressive behavior is a common manifestation of problem behaviors, and several previous studies suggested that neuroticism has characteristics such as oversensitivity and impulsivity, which may be important predictors of aggressive behavior. However, the mediating mechanisms underlying this relationship are unknown. This study is designed to analyze how neuroticism leads to left-behind children’s aggressive behaviors through mediators of interpersonal sensitivity and bullying victimization. A sample of 1478 Chinese children (67.72% left-behind children; 37.28% non-left-behind children) through whole-class contact and voluntary participation completed measurements of neuroticism, interpersonal sensitivity, bullying victimization, and aggressive behavior. Findings from the mediation analysis show that interpersonal sensitivity and bullying victimization could mediate the relationship between neuroticism and aggressive behavior among left-behind children separately and sequentially. These findings suggest helpful ways to reduce the aggressive behaviors of left-behind children by decreasing interpersonal sensitivity and bullying victimization.