Purpose: Globally, alcohol use is the leading cause of ill health and life years lost in adolescents, although its clinical impact is often overlooked, particularly in England where most research is based in schools. This study aims to examine the prevalence of alcohol consumption and the association between alcohol consumption and age of onset with health and social consequences among adolescents presenting to emergency departments (EDs). Methods: Consecutive attenders (n = 5,576) aged 10-17 years at 10 EDs were included. Information was collected on general health and functioning, quality of life, alcohol use, and alcohol-related health and social consequences. Results: Nearly 40% of adolescents reported the consumption of alcohol that was more than a sip in their lifetime. Age of the first alcohol consumption before the age of 15 years was associated with tobacco use (p < .001), lower quality of life (p = .003), and evidence of an alcohol use disorder (p = .002). It was also associated with general social functioning (problems with conduct p = .001 and hyperactivity p = .001) and alcohol-related health and social consequences (accident p = .046, problems with a parent p = .017, school p = .0117, or police p = .012). Conclusions: Rates of alcohol consumption in adolescents presenting to the ED were similar to those reported in schools in England and globally. Associations of alcohol consumption and earlier onset of drinking with poorer health and social functioning were observed. The ED can offer an opportunity for the identification of hazardous alcohol use in adolescents.