Objective: The purpose of this study was to determine whether parents' and children's reports of parenting practices were correlated, whether the reports were differentially associated with alcohol use, and which report had the strongest association with alcohol use. Method: We carried out a cross-sectional and longitudinal study in public schools in Chicago, IL. Participants included 1373 ethnically diverse students and parents involved in an alcohol use prevention intervention. Surveys were conducted with sixth-grade and eighth-grade students. Mixed-effects regression analyses were used to model relationships cross-sectionally and longitudinally. Results: Parents' and children's perceptions of parenting practices, while significantly correlated, were not strongly associated. Analyses within each parenting domain found parents' report of parental monitoring and children's reports of alcohol-specific communication, general communication and relationship satisfaction were associated with alcohol use behaviours and intentions. After adjusting for all other parenting practices, parents' report of parental monitoring and children's report of alcohol-specific communication were most strongly related to alcohol use behaviours and intentions both cross-sectionally and longitudinally. Conclusions: When comparing results across studies, it is important to identify whose report was used, parent or child, as the results may differ based on the reporter. Studies with limited resources may consider using parents' reports about parental monitoring and using children's reports for alcohol-specific communication, general communication and relationship satisfaction. (Contains 5 tables.)