Purpose: This research has been conducted in order to understand the major factors that affect self-esteem of adolescents. Methods: Data was collected by questionnaires from 1155 students at middle and high school in Seoul and Kyungkido, Korea. The Instrument tools utilized in this study were self-esteem, body-image, problematic behavior, depression, school adjustment, social support tool and thoroughly modified to verify validity and reliability. The collected data have been analyzed using SPSS 11.0 program. The variable of family harmony and counseling partner was treated as a dummy variable. Seven outliers which were bigger than 3 in absolute value were found, so after taking them off, Multiple Regression was used for further analysis. Result: The major factors that affect self-esteem of adolescents were depression, social support, body-image, problematic behavior, school adjustment, and family harmony, which explained 54.7% of self-esteem. Conclusion: It has been confirmed that the regression equation model of this research may serve as a self-esteem prediction factors in adolescents.