ABSTRACT. Objective: Lesbian, gay, bisexual, and transgender (LGBT) youth are at increased risk for alcohol misuse, but little is known about the psychosocial and demographic factors that are associated with these differences over time. The purpose of this study was to investigate change in alcohol use across development. We aimed to describe group/ demographic differences in alcohol use, the effects of psychosocial variables on drinking within persons (i.e., psychological distress, sexual orientation-based victimization, and perceived family support), and the interactions between demographic differences and longitudinal psychosocial variables in predicting rates of alcohol use. Method: The current study used data from the longest running longitudinal study of LGBT youth. Hierarchical linear modeling was used to examine both demographic differences and psychosocial predictors of alcohol use in an ethnically diverse sample of 246 LGBT youth (ages 16-20 years at baseline) across fi ve time points over 2.5 years. Results: Drinking increased signifi cantly over time in a linear fashion, although it tended to increase more rapidly among male LGBT youth compared with females. Analyses of group differences revealed lower average rates of drinking for African American and female LGBT youth, and there were no differences between bisexual youth and gay/lesbian youth. Psychological distress and sexual orientation-based victimization were associated with increased alcohol use at each wave of data collection for female LGBT youth only. Perceived family support at each wave was negatively associated with alcohol use for all LGBT youth. Conclusions: Findings indicate that there is signifi cant heterogeneity in the etiological pathways that lead to alcohol use in LGBT youth and that correlates of drinking are similar to those found in general populations. These crucial fi ndings indicate that existing alcohol interventions also may be effective for LGBT youth and open up a wider array of prevention and treatment options for this at-risk population. (J. Stud. Alcohol Drugs, 73, 783-793, 2012)