The prevalence of aggression in adolescents is on the rise, and it could be a serious public health concern. Studies have found positive relationships between perfectionism with anger, aggression, and hostility. However, the moderating role of self-compassion in the links between perfectionism with anger, aggression, and hostility has not been studied. To better understand the relationships between the three forms of perfectionism with anger, aggression, and hostility, this study aimed to explore the moderating role of self-compassion. Participants were 380 undergraduates selected using a multi-stage cluster sampling technique from three universities in Iran. Participants completed the Self-Compassion Scale, the Multidimensional Perfectionism Scale, and the Aggression Questionnaire Scale. The results from structural equation modelling analysis showed that other-oriented perfectionism and socially prescribed perfectionism positively predicted anger, aggression, and hostility. The results showed that self-oriented perfectionism significantly and positively predicted anger and hostility; but there were no observed statistically significant relationships of self-oriented perfectionism with verbal aggression and physical aggression. The findings showed that self-compassion played a moderating role in the relationships between other-oriented perfectionism and socially prescribed perfectionism with anger, aggression, and hostility; however, it did not play a moderating effect on self-oriented perfectionism with anger, aggression, and hostility. The findings provide a deeper understanding of the moderating role of self-compassion in the links between other-oriented perfectionism and socially prescribed perfectionism with anger, aggression, and hostility among undergraduates. The findings of this study could be applicable for psychologists and counselors who deal with aggressive behavior, anger, and hostility in undergraduate students to assess the three forms of perfectionism and self-compassion.