Objectives: The purpose of this study was to examine the influence of father-adolescent attachment on adolescents’ internalizing behavior problems within the Mongolian family context. Additionally, the moderation effect of adolescents’ gender was also examined.Methods: One hundred seventy four Mongolian adolescents who lived in Ulaanbaatar, Mongolia participated in this study. The participants was 13 to 15 years old, and 69 out of 174 participants were boys. Consent was taken from participants and their parents. Instructions, consent forms, and questionnaires written in English were translated into Mongolian language. Participants responded to questionnaires that measured attachment to fathers, adolescents’ depression, and anxiety. Data were analyzed using hierarchical multiple regression.Results: Results of this study showed that there was a significant difference between sons and daughters in the attachment to their fathers. Attachment security between sons and fathers was higher than that between daughters and fathers. Gender differences were also found in adolescents’ depression and anxiety. Levels of depression and anxiety in girls were significantly higher than in boys. In addition, attachment to fathers negatively predicted adolescents’ internalizing behavior problems including depression and anxiety. In particular, the moderation effect of adolescents’ gender was also significant. Specificially, girls’ attachment to fathers negatively predicted girls’ internalizing behavior problems, but no significant finding was reported in the relationship between fathers and boys.Conclusion: Findings suggested a protective role of adolescents’ attachment to fathers against adolescents’ internalizing behavior problems, and were discussed in terms of characteristics of parent-child relationship in Mongolian culture. The role of attachment on adolescents’ mental health was suggested.