Alcohol use among Biracial adolescents remains understudied. This study examined how parenting and peer factors relate to age of alcohol use onset among Black, White, and Biracial Black-White adolescents and emerging adults. We used Add Health data to produce a final analytic sample of 13,528 adolescents who self-identified as White, Black, or Biracial Black-White. Discrete-time survival analysis implemented within logistic regression indicated Black adolescents showed the lowest probability of alcohol use onset by age 18, followed by Biracial adolescents, and White adolescents. The probability of alcohol use onset increased for Monoracial Black and White adolescents at ages 16, 18, and 21. Descriptively our model suggest that Biracial adolescents exhibit a sharp decline in their probability of alcohol use onset at age 16 and a sharp increase at age 21. However, this trend did not differ significantly from the other racial groups. Consistent with social control and learning theories, low parental acceptance, high parental control, and peer substance use were associated with alcohol use onset. Alcohol use onset trajectories differed for Monoracial and Biracial adolescents with Biracial individuals reporting greater alcohol onset in adulthood. Prevention efforts should continue to target parental acceptance, parental control, and peer substance use.