Objectives. We examined sexual orientation status differences in alcohol use among youths aged 13 to 18 years or older, and whether differences were moderated by sex, age, or race/ethnicity. Methods. We pooled data from the 2005 and 2007 Youth Risk Behavior Surveys and conducted weighted analyses, adjusting for complex design effects. We operationalized sexual orientation status with items assessing sexual orientation identity, sexual behavior, sexual attraction, or combinations of these. Results. Compared with exclusively heterosexual youths, sexual-minority youths were more likely to report each of the primary study outcomes (i.e., lifetime and past-month alcohol use, past-month heavy episodic drinking, earlier onset of drinking, and more frequent past-month drinking). Alcohol-use disparities were larger and more robust for (1) bisexual youths than lesbian or gay youths, (2) girls than boys, and (3) younger than older youths. Few differences in outcomes were moderated by race/ethnicity. Conclusions. Bisexual youths, sexual-minority girls, and younger sexual-minority youths showed the largest alcohol-use disparities. Research is needed that focuses on identifying explanatory or mediating mechanisms, psychiatric or mental health comorbidities, and long-term consequences of early onset alcohol use, particularly frequent or heavy use, among sexual-minority youths.