We examined the effects of gender and classroom membership on moral disengagement-cognitive justifications of detrimental conduct. Sixth-graders aged 11 to 13 years (N = 273) participated in the study. Bullying was registered using the Olweus Bully/Victim Questionnaire and moral disengagement was measured on a 14-item scale designed for this study. The study showed that moral disengagement related to bullying and varied as a function of gender, which supports the relevance of considering gender in moral education anti-bullying programs. Next, the study revealed significant differences in moral disengagement between classrooms. This finding points to the need to elucidate associations between moral disengagement and classroom characteristics.