Alcohol use during adolescence is a major public health concern, in particular because the brain is still developing and undergoing considerable structural and functional changes. Identifying risk factors that influence adolescent alcohol use is important to appropriately target prevention programs. One area of research that has received considerable attention is the role cognitive functioning (e.g., working memory and inhibition) play as risk for involvement in adolescent alcohol use. There is also a large literature showing a relationship between substance use and self-harm. It is possible that alcohol may increase the risk of self-harm by lowering inhibitions and impairing working memory, which is central to decision making. There is also evidence to suggest that there may be a bi-directional relationship, as several longitudinal studies have reported an association between adolescent self-harm and alcohol problems in adulthood. Although previous prospective studies have examined this association, they are often limited by the use of small sample size, different alcohol use phenotype (i.e. bingeing vs frequency), different follow-up periods, or lack of control for relevant confounders.