Background: Early contact with the justice system is associated with a multitude of negative outcomes across the life course. This includes an increased risk of ongoing justice contact, social disadvantage and marginalization, and mental health and substance use issues. Children whose mothers have an alcohol use disorder may be at risk of early justice system contact, and we sought to quantify this relationship in a Western Australian cohort. Methods: This population cohort study made use of linked administrative data. Those in-scope for the study were women who had a birth recorded on the Midwives Notification System (1983 to 2007). The exposed cohort were mothers who had an alcohol-related diagnosis (ICD9/10), recorded on administrative data. This included mental and behavioral disorders which were alcohol related, diseases which could be entirely attributed to alcohol and other ICD alcohol codes. These women were considered to have an alcohol use disorder, which was a proxy for heavy drinking. The comparison cohort was frequency-matched sample with no alcohol-related diagnosis identified on administrative data sets. Results: After adjusting for potential confounders, children whose mothers had a maternal alcohol use disorder had a significantly increased odds of justice contact when compared to those whose mothers had no diagnosis (odds ratio [OR] = 1.79, 95% confidence interval [CI] = 1.60 to 1.99). Additional significant maternal factors associated with child justice contact included being Indigenous (OR = 5.14, 95% CI = 4.54 to 5.81), low maternal age, low socioeconomic status, being unmarried, and a history of a mental health problems. Significant child-level factors, which were associated with increased odds of justice contact, included being male, a mental health diagnosis, child protection contact, parity, and academic failure. Conclusions: Children who were exposed to a maternal alcohol use disorder had significantly increased odds of contact with the justice system. Additional risk was associated with being Indigenous and with markers of social disadvantage. These results suggest that prevention and early intervention services should span across agencies in an effort to reduce risk.