Self-serving cognitions and callous-unemotional traits play important roles in adolescent antisocial behavior. The objective of this study was to cross-sectionally explore the mediating role of self-serving cognitions in the relationship between callous-unemotional traits and antisocial behavior. A sample of 972 high-school students completed self-report questionnaires assessing callous-unemotional traits, self-serving cognitive distortions and antisocial behavior. Two competing models exploring indirect effects accounting for the relationships between self-serving cognitive distortions, callous-unemotional traits and antisocial behaviors were tested. Both models revealed significant indirect effects, suggesting both pathways are possible. Gender was found to moderate these models. These findings suggest the importance of targeting self-serving cognitions in therapeutic interventions and increase our understanding of the role of self-serving cognitions in antisocial behavior.