Bullying has damaging short-term and long-term consequences. Research suggests that perpetrators have low empathy and high moral disengagement, but relations between these variables are unclear and are rarely integrated in a single study. Thus, the objective of this study was to discover if empathy and moral disengagement mechanisms were related to bullying perpetration. This study was conducted with 904 Polish adolescents enrolled in 6 rural and urban upper secondary schools. High affective empathy predicted lower bullying perpetration. Moral-disengagement mechanisms such as (...) moral justification, euphemistic language, advanced comparison, and distorting consequences were uniquely related to increased bullying perpetration. Low affective empathy was also uniquely related to increased perpetration. These findings have important implication for school policy and practice. (shrink)