Objective: Alcohol misuse is a prevalent problem among military service members and their spouses. Service member alcohol misuse may contribute to poor job performance, legal infractions, and failure to meet physical standards. Spousal alcohol misuse may indicate problems with military life. However, limited information is available about how alcohol misuse in military families affects occupational outcomes, specifically military attrition. Method: The current study examined 7,965 opposite sex married couples from the Millennium Cohort Family Study with one military and one civilian/veteran partner. Both partners reported on three measures of alcohol misuse (binge drinking, alcohol problems, and heavy weekly drinking). The associations between each partner's measures of alcohol misuse and subsequent military separation were evaluated using logistic regression. Sex, concordance of alcohol misuse, mental health, and service branch were explored as moderators. Results: In fully adjusted models, service member alcohol problems were directly related to military separation. Additionally, service member heavy weekly drinking was strongly associated with military separation among female service members but not male service members. Service member and spouse binge drinking interacted such that when only one partner reported binge drinking military separation was less likely, but both partners' binge drinking conveyed a marginally increased risk of military separation. Conclusions: Prevalence of alcohol misuse was high among military families. Service member alcohol misuse was more strongly related to military separation than spouse alcohol misuse. Additionally, heavy weekly drinking among female service members may be an indicator of a significant issue that merits interventions aimed at retaining these service members.