Even though research indicates a decline in adolescent substance use since its peak in the 1970's, a significant proportion of youth still report either drinking alcohol and/or smoking marijuana. Past research also indicates that family factors, such as parental attachment, parental monitoring, and parental substance use are key to understanding the developmental processes leading to substance use. This study utilized Gottfredson and Hirschi’s General Theory of Crime (1990) and their concept of self-control to examine the indirect role that parental behavior plays in preventing or allowing substance use and whether parental variables work indirectly through adolescent self-control to prevent youths’ substance use. The study begins with a literature review of the demographic trends in adolescent substance use, the effects of parental attachment, monitoring, and parental substance use on adolescent substance use, and on self-control and adolescent substance use. Data for the study were taken from the Children of the National Longitudinal Survey of Youth (NLSY), a nationally representative longitudinal sample of youth aged 14 to 21 in 1979. The results indicate that parental factors directly affect youth’s substance use via self-control. Also, two of the parenting and parental behavior variables, parental monitoring and maternal marijuana use, have additional direct effects on adolescent substance us. High self-control was significantly associated with high maternal attachment, high parental monitoring, and sex (girls having higher levels of self-control). Study implications and limitations are presented and discussed. References and appendix