Adolescent alcohol involvement may increase risk for young-adult depression; however, findings are mixed and important questions remain unanswered. Because alcohol involvement among teens is multidimensional, this study examined the extent to which four different adolescent alcohol dimensions (i.e., frequency of alcohol use, quantity of consumption, frequency of heavy episodic drinking, and frequency of problem use) were predictive of young-adult major depressive disorder (MDD). Participants in this prospective longitudinal study, which extended from age 11 to age 22, were 429 rural teens (including 222 girls) and their families. Self-reports of each dimension of adolescent alcohol involvement were obtained at ages 16 and 18. Depression diagnoses were obtained at age 22, using a structured interview. Analyses included adolescent depressed mood, measured via self-report at ages 16 and 18. Data were analyzed using confirmatory factor analysis and structural equation modeling. The multidimensional nature of adolescent alcohol involvement was best represented by a first-order problem-use factor and a second-order alcohol-intake factor comprised of quantity, frequency, and heavy drinking. After controlling for gender and depressed mood, adolescent problem use, but not alcohol intake, was a significant positive predictor of young-adult MDD. Findings help clarify the link between alcohol involvement and depression and suggest that harm-reduction strategies may help prevent later mood disorders.