Objectives: The purpose of this study was to investigate the differences of oral health level according to the socioeconomic status of adolescents and to analyze the role of oral health behaviors and psychological factors on oral health inequality. Methods: Analysis were based on 61,086 adolescents who responded their parents' education level of Adolescent Health Behavior Online Survey (KYRBS) in 2016. Multivariate logistic regression analysis was used to test four conditions for the difference of oral health level according to the socioeconomic status when the effects of oral health behaviors and psychological factors were controlled. Results: The results showed that the inequality is present in oral health. After adjusting oral health behaviors and psychological factors, the odds ratio of oral health according to socioeconomic status decreased, but the significant difference in oral health according to socioeconomic status did not change. Conclusions: In order to reduce the oral health inequality among adolescents, the approach strategies focusing on the social environment that affects oral health inequality are important.