Recent research has suggested that there are twodistinct trajectories for the development of antisocial behavior in boys: a childhood-onsetpathway and an adolescent-onset pathway. After reviewing the limited available research onantisocial girls, we propose that this influential method of conceptualizing the development ofsevere antisocial behavior may not apply to girls without some important modifications.Antisocial girls appear to show many of the correlates that have been associated with thechildhood-onset pathway in boys, and they tend to show impaired adult adjustment, which is alsosimilar to boys in the childhood-onset pathway. However, antisocial girls typically show anadolescent-onset to their antisocial behavior. We have proposed that these girls show a thirddevelopmental pathway which we have labeled the “delayed-onset” pathway. Thismodel rests on the assumption that many of the putative pathogenic mechanisms that contributeto the development of antisocial behavior in girls, such as cognitive and neuropsychologicaldeficits, a dysfunctional family environment, and/or the presence of a callous andunemotional interpersonal style, may be present in childhood, but they do not lead to severe andovert antisocial behavior until adolescence. Therefore, we propose that the delayed-onsetpathway for girls is analogous to the childhood-onset pathway in boys and that there is noanalogous pathway in girls to the adolescent-onset pathway in boys. Although this model clearlyneeds to be tested in future research, it highlights the need to test the applicability of currenttheoretical models for explaining the development of antisocial behavior in girls.