This study examines the basis and change of delinquent behavior among Korean adolescents. Theoretical framework was developed and qualitative analysis of delinquency behavior was examined. In order to understand the basis and change of juvenile delinquency, the influence of family environment, school environment and individual factors were investigated through cross-sectional and longitudinal studies. The results of the findings can be summarized into the following six main points: 1) two subcultures of adolescent functioning could be ascertained, 2) the decrease in social support and increase in moral disengagement were directly related to a rise in juvenile delinquency, 3) family disintegration contributed to juvenile delinquency, 4) peer influence help to raise juvenile delinquency, 5) schools were unable to give hope to those students who were not doing well in school and were ineffective in dealing with juvenile delinquents, and 6) the phenomenon of juvenile delinquency points to the importance of opening up the closed school system and closed society, allowing individual diversity and skills to be recognized.