Background: Studies have consistently found that parental and peer drinking behaviors significantly influence adolescent drinking behavior and that adolescent drinking has a significant effect on their drinking-and-driving behavior. Building upon these studies, the present article assesses whether parental and peer drinking behaviors have direct and indirect effects on adolescent drinking and driving as well as whether they moderate the effect of adolescent drinking on their drinking-and-driving behavior. Methods: The assessment is conducted using data collected from the Buffalo Longitudinal Survey of Young Men (BLSYM) with Ordinary Least Squares (OLS) regression analyses. Results: The data reveal that peer drinking has direct and indirect effects on adolescent drinking-and-driving behavior when adolescent drinking behavior is controlled. It also moderates the effect of adolescent drinking behavior on their drinking and driving. However, parental drinking does not have these direct and interactive effects, although it may have an indirect effect on adolescent drinking and driving via adolescent drinking behavior. Conclusions: These findings imply that peer drinking behavior should be considered seriously in prevention and intervention for reducing the risk of adolescent drinking-and-driving behavior. (Contains 4 tables and 2 footnotes.)