This study examined developmental processes linking competence and psychopathology in an urban sample of girls during their transition to adolescence. Longitudinal associations among indices of externalizing symptoms, social competence, and internalizing symptoms were also tested within contexts of family adversity and girls' pubertal status. Child, parent, and teacher report were employed to assess core constructs across six annual assessment waves, starting at age 9. Results revealed the significant effect of prior levels of externalizing symptoms on changes in social competence and internalizing symptoms, as well as reciprocal relations between social competence and internalizing symptoms. In addition, girl's maladaptive functioning predicted increases in family adversity exposure over time. Last, more mature pubertal status in early assessment waves was linked to an increase in internalizing symptoms; however, this association was reversed by the last assessment, when most girls had reached advance stages of puberty. The timing of these effects reveals important targets for future interventions aimed at promoting the successful adaptation of girls in adolescence.