There has been relatively little research examining the relationship between parents’ disclosure of their own underage (i.e., under 21 years) alcohol use and their children’s alcohol-related attitudes and behaviors. While parental disclosure may improve trust and understanding within a relationship, it may also normalize or glamorize underage alcohol use. The current study examines the longitudinal relationships among mothers’ disclosure of underage alcohol use, mothers’ current alcohol use, and college students’ alcohol-related attitudes and behaviors. College students under the age of 21 completed measures of maternal disclosure of underage alcohol use (no disclosure, disclosure of use only, disclosure of negative consequences), maternal modeling, and student alcohol attitudes, use, and consequences. Approximately 7 months later, students completed additional measures of alcohol outcomes. The longitudinal model suggests that disclosure is associated with students drinking more alcohol and experiencing greater consequences. There were no significant differences in outcomes for students whose mothers disclosed use of alcohol and those whose mothers discussed the negative experiences they had had because of underage alcohol use. The results of the current study suggest that maternal disclosure of their own underage alcohol use, regardless of whether negative experiences are discussed, is associated with greater subsequent alcohol use and problems among college students.