AbstractPurpose To estimate the prevalence of alcohol use at the age of 10–11 years and document variation by early sociodemographic and concurrent alcohol-specific risk factors. Methods The Millennium Cohort Study is a prospective, nationally representative study of live births in the United Kingdom across 12 months. A random sample of electoral wards was stratified to adequately represent U.K. countries, economically deprived areas, and areas with high concentrations of Asian and Black British families. A total of 12,305 child–mother pairs provided self-report data at 9 months (mother's marital status, age, education, occupational level; child gender, ethnicity, country) and age 10–11 years (adolescent alcohol use and attitudes). Results After adjusting for attrition and sampling design, 13.4% of 10- to 11-year-olds had had an alcoholic drink (more than few sips), 1.2% had felt drunk, and .6% had five or more drinks at a time. Odds of ever drinking were higher among boys (1.47, 95% confidence interval, 1.29–1.68) and lower among early adolescents who were Asian British (vs. white; .09, .05–.17) or Black British (.42, .29–.62). Beyond sociodemographic differences, more positive attitudes about alcohol were associated with greater odds of drinking (1.70, 1.51–1.91), feeling drunk (2.96, 2.07–4.24), and having five or more drinks (4.20, 2.66–6.61). Conclusions Alcohol use in the last year of primary school was identified but not common. Its use varied by sociodemographic groups; early adolescents with more positive alcohol attitudes had especially high risks of early alcohol initiation. Results support calls for increased surveillance and screening for very early drinking.