Abstract: Moral disengagement involves a process of cognitive re-construing or re-framing of destructive behavior as morally acceptable. Relational aggression is a type of conceal aggression in which harm is caused by damaging someone's relationships or social status. The study used situational experiment and questionnaire methods to explore the impact of moral disengagement on relational aggression. Data were collected from 1087 middle school students. Results demonstrated that moral disengagement could significantly predict all three dimensions of relational aggression, including moral justification, blurring causality and distorting harmful effects. Male students got significantly higher scores on moral disengagement than female students, but there was no gender difference on scores of relational aggression. Students from rural areas got significantly higher scores on relational aggression than students from cities, the same results also found on scores of distorted harmful effects and obscuring causal relationship.

Key words: moral disengagement, relational aggression, gender difference, rural-urban difference