ObjectiveAdverse childhood experiences (ACEs) are associated with increased risk of sustaining a traumatic brain injury (TBI). Alcohol use may play an important role in this relationship. This study examines whether binge drinking mediates the relationship between four ACEs and TBIs sustained in adulthood.MethodsUsing the National Longitudinal Survey of Youth, 1979 cohort, we conducted longitudinal mediation analyses (n=6317). Interviews occurred annually from 1979 to 1994 and biennially until 2016. We evaluated the direct and indirect effects of individual ACEs (ie, experiencing physical violence, low parental warmth, familial alcoholism and familial mental illness; reported retrospectively) and a cumulative ACEs score on mean level of binge drinking (calculated across waves) and having a TBI in adulthood. To establish temporality, we included binge drinking that was measured at age 18 or older and before any reported TBI.ResultsCumulative ACEs, familial alcoholism and physical abuse exposure were significantly associated with having a TBI through binge drinking, although this only explained a small part of the association between ACEs and TBI. Other ACEs were not significantly associated with binge drinking or TBI.ConclusionThe results indicate that while ACEs and adult TBI risk were significantly associated, lifetime binge drinking explains only a small part of the association. Future research could examine alternative social, biological and behavioural mechanisms along the pathway between ACEs and TBI. Determining this mechanism will allow public health practitioners to design and implement effective TBI prevention programmes for those at higher risk of injury due to ACE exposure.