PURPOSE: The purpose of this study was to examine risk factors for sexual behaviors in Korean female high school students. METHOD: Data was collected by a written questionnaire from June 22 to July 18, 2002 from 522 girls, who were stratified samples from a target population of 63,375 11th grade students from 200 regular high schools and 70 vocational high schools in Seoul, Korea. We conducted multiple regression analysis using the SAS pc+ program. RESULT: Risk factors for intimate behaviors were association with boy friends, differential association, family attachment, and family abuse experience. These variables cause 68% of intimate behaviors. Risk factors for sexual experiences were differential association, association with boy friend, and family attachment. These variables cause 14% of sexual experiences. CONCLUSION: Efforts to reduce sexual behaviors in girls should include the possible role of peers and develop peer leader programs.