The purpose of this study was to explore the general tendencies of major variables and sex differences and to analyze the variables that affect delinquency and aggression. The protective factors considered in this study included parental education participation, parental supervision, and peer attachment, and the risk factors were academic stress and delinquency experiences of peers. The main results of this study are as follows: firstly, academic stress and parental education participation was slightly low, but parental supervision was high. Further, peer attachment showed a very high score. Delinquency experiences of peers, delinquency, and aggression of adolescents were extremely low. Secondly, the correlation of parental education participation, parental supervision, and peer attachment was negatively related to adolescent delinquency, but the delinquency experiences of peers were positively related to adolescent delinquency. The same results were obtained in the case of adolescent aggression. Further, academic stress was negatively related to adolescent aggression. Finally, hierarchical regression revealed that the variables explaining the juvenile delinquency were parental education participation, peer attachment, and delinquency experiences of peers. Adolescent aggression was explained by sex, academic stress, parental education participation, and the delinquency experiences of peers. In particular, more attention is needed for girls. Various interventions should be provided to prevent problem behaviors.