This study investigated the integrated effects of family and school factors on the cyber behavior of adolescents. Specifically, the purposes of this study were to categorize adolescents into groups by family and school factors and to find investigate differences among the groups regarding cyber behavior (internet use, internet purpose, and internet experience). no study distributed the questionnaires to middle and high school adolescent students of five representative cities in South Korea. The total respondents were 2240 (960 from Seoul/kyongki, and 320 each from Taegu, Pusan, Kwangiu, and Taejon). The response rate w3s 98.7%. no data were analyzed by factor analysis, cluster analysis, ANOVA, and Duncan test. The results showed that Korean adolescents were segmented into four groups (family preference/school preference group, family dissatisfaction/teacher dissatisfaction group, family average/school average group, family average/peer dissatisfaction group). The four groups were significantly different in regard to cyber behavior. For example, the family dissatisfaction/teacher dissatisfaction group u%d internet to relieve stress and used communication more than the other groups. Also, the group had more diverse cyber behavior including internet addiction. The implications of the study were further discussed.