The aim of the present study was to examine to what degree different mechanisms of moral disengagement were related to age, gender, bullying, and defending among school children. Three hundred and seventy-two Swedish children ranging in age from 10 to 14 years completed a questionnaire. Findings revealed that boys expressed significantly higher levels of moral justification, euphemistic labeling, diffusion of responsibility, distorting consequences, and victim attribution, as compared with girls. Whereas boys bullied others significantly more often than girls, age was unrelated to bullying. Moral justification and victim attribution were the only dimensions of moral disengagement that significantly related to bullying. Furthermore, younger children and girls were more likely to defend victims. Diffusion of responsibility and victim attribution were significantly and negatively related to defending, while the other dimensions of moral disengagement were unrelated to defending. Aggr. Behav. 40:99–108, 2014. © 2013 Wiley Periodicals, Inc.