Children who show elevated levels of indirect aggression (IA) from childhood to adolescence are at increased risks of experiencing detrimental outcomes. Some studies suggest that psychopathic traits could act as a predisposing vulnerability in the development of IA, but the contributions of all three dimensions of psychopathic traits in explaining developmental trajectories of IA from childhood to adolescence remain unclear. This study aimed to determine if the three dimensions of psychopathic traits during childhood (i.e., callous-unemotional, narcissism-grandiosity, and impulsivity-irresponsibility at 6-9 years old) increase the risk of following a high IA trajectory across preadolescence, and whether sex moderated these associations. Participants were 744 children (47% girls; 93% born in Quebec, Canada, and over 50% from low socioeconomic backgrounds) assessed annually over 5 years. Approximately half of them (n = 370; 40.3% girls) were referred to school-based services for conduct problems (CP) at study intake. Latent class growth analyses revealed four developmental trajectories of IA, which were regressed on psychopathic traits dimensions using a three-step approach. After adjusting for demographic confounders, CP, and other dimensions of psychopathic traits, only narcissism-grandiosity traits significantly predicted memberships to a high and stable trajectory of IA use. The associations between the other dimensions of psychopathic traits and IA trajectories were not significant when considering confounders. No moderating effects by child sex were observed. These results suggest that narcissism-grandiosity traits could be of use for clinicians aiming to detect children most at risk of showing high and persistent levels of IA.