Background: Adolescents’ health risk behaviors tend to increase during the high school years. Parental control from the family may serve as protective factors against substance use and early sexual activity. Aim: In this study, we aim to examine the prevalence of health-risk behaviors, namely alcohol consumption, tobacco use, and risky sexual practices among Mongolian adolescents, and to evaluate the impact of parental monitoring on these behaviors. Method: Participants of this cross-sectional survey were Mongolian adolescents (N = 312) from 9th to 12th grades of high schools living in provinces. The self-completed questionnaire included items on the students’ sexual behavior and substance use (Health Behavior in School aged Children, HBSC study; Inchley et al., 2018) and parental control (Parental Monitoring Instrument; Cottrell et al., 2007). Results: Seven forms of parental monitoring were measured: direct and indirect, school, health, computer, phone, and restrictive monitoring. The parents’ indirect monitoring declined with age (r =-0.12, p <0.05). Among the forms of parental control, phone monitoring showed the strongest correlations with adolescent behaviors: having a boy or girlfriend (r = -0.25, p <0.001) and having sexual intercourse (r =-0.21, p <0.001). Besides, restrictive monitoring also played a role in having a boy or girlfriend (r = -15, p <0.01) and previous sexual experiences (r = -11, p<0.05). Conclusion Parental monitoring might play a lesser role in adolescent substance use as we expected. In contrast, certain form of parental control, namely, phone and restrictive monitoring might prevent adolescents from early sexual activity.