The purpose of the present study was to examine the direct and indirect effects (through peer contacts) of parental knowledge on adolescents' delinquent and aggressive problem behavior, using latent growth curve modeling. A sample of 457 13- to 14-year old adolescents at first measurement wave (M = 13.27; SD = 0.45 years) filled out questionnaires about their parents, peers, and problem behavior three times with 1-year intervals in between. Regarding initial levels of behavior, both direct and indirect effects of parental knowledge were found on aggressive as well as on delinquent behavior. When the rate of change in behaviors was considered, only direct effects were found for both types of problem behavior, whereas indirect effects were absent. Gender differences were also found, with stronger effects of parenting on both aggressive and delinquent problem behavior for boys and stronger effects of peer contacts on aggressive behavior for girls. The present study shows that different behaviors of the externalizing spectrum have different trajectories and diverse relations with parenting and should not be treated as identical.