Parents' alcohol use may influence adolescent substance use and substance use intentions. Prior research has linked adolescents' emotion reactivity with parental drinking behaviors and adolescent substance use. The present study investigated whether sub-clinical maternal alcohol use relates to adolescent neural emotion reactivity and substance use intentions in early adolescence. Early adolescents (N = 70) viewed emotional images during a fMRI scan and completed a questionnaire about substance use intentions. Their mothers reported past 30-day alcohol use. Results showed that greater frequency of maternal alcohol use predicted adolescents' substance use intentions. In addition, maternal alcohol use predicted adolescent blunted responses to positive emotional images in the ventromedial prefrontal cortex (vmPFC) and bilateral anterior cingulate cortex (ACC). There was no relationship between neural emotion reactivity and adolescent substance use intentions. Findings suggest that parental alcohol use may relate to adolescent's development of reward and positive emotion processing systems, even at sub-clinical levels of drinking.