Adolescents of parents who use substances are at an increased risk for substance use themselves. Both parental monitoring and closeness have been shown to mediate the relationship between parents' and their adolescents' substance use. However, we know little about whether these relationships vary across different substances used by adolescents. Using structural equation modeling, we examined these associations within a racially and ethnically diverse sample of 9th and 10th graders (N = 927). Path analyses indicated that maternal closeness partially mediated the association between maternal problematic substance use and adolescent alcohol use. Parental monitoring partially mediated the relationship between paternal problematic substance use and adolescent alcohol, cigarette, marijuana, inhalant, and illicit prescription drug use. These results were consistent across gender and race/ethnicity. These findings suggest that parental interventions designed to increase closeness and monitoring may help to reduce adolescent substance use.