The purpose of this research was to clarify the impact of sexual abuse experienced by female adolescents on depression and to examine mediation effects of distorted beliefs related to sex. Self-report questionnaires were distributed to middle and high school female students in Seouland Gyonggi Areas. The549responseswereanalyzedbyregressionanalysis. Results indicated that 22.2% of the respondents had experienced sexual abuse; the experience of sexual abuse had a significant effect on distorted sex-related belief, but not on depression. Distorted sex-related beliefs, however, mediated between the experience of sexual abuse and depression. This study suggests the necessity for intervention and practical methods for the prevention of adolescent sexual abuse.