The aim of the current study was to examine whether collective moral disengagement in the classroom was associated with bullying perpetration and victimisation. One-thousand-and-fifty-four students from 70 classrooms in 29 schools in the middle and southern parts of Sweden completed a questionnaire in their classroom. In line with the hypotheses, the bivariate correlation analyses at the classroom level showed that students who belonged to classrooms with lower collective moral disengagement were less likely to be victimised by bullying or engaged in bullying perpetration. Moreover, when controlling for gender and age at the individual level and including collective moral disengagement in the same model at the classroom level, multilevel analyses revealed that students who belonged to classrooms with a higher level of collective moral disengagement were more likely to be engaged in bullying perpetration or to be targets of bullying victimisation.