The purpose of the present study which regards bullying as a group process was to examine the direct and indirect influences of moral disengagement, empathy, and guilt on bullying assistant behavior. The participants consisted of 442 6th graders from an elementary school(male : 227, female : 215). The findings from this study are as follows. First, there are significant correlations between moral disengagement, empathy, guilt, and bullying assistant behavior. Second, moral disengagement have not only direct influences but also indirect influences through empathy and guilt on bullying assistant behavior. Moral disengagement was the strongest predictor of bullying assistant behavior. Finally, the implications for future research and intervention in bullying were also discussed.