Sexual minority women (SMW; individuals who identify as women and as lesbian, bisexual, or with another sexual minority identity) are at increased risk for problematic alcohol use compared to their heterosexual counterparts. This increased risk has been attributed to minority stress. However, longitudinal research examining associations between minority stress and alcohol use outcomes is extremely limited and examinations of these associations at the daily level are nearly non-existent. Further, few longitudinal studies have examined mechanisms through which minority stress may impact alcohol use. We utilized data from a 14-day daily diary study of 98 SMW to examine daily-level associations between experiences of minority stress, alcohol consumption and consequences, and two proposed mediators of these associations (perceived coping efficacy, social interaction anxiety). Results indicated that on days when participants experienced minority stress events, they experienced lower coping efficacy, higher social interaction anxiety, and more drinking consequences than usual. Minority stress was not associated with same-day alcohol consumption. Perceived coping efficacy and social interaction anxiety mediated the same-day association between minority stress and drinking consequences. No prospective associations were significant, suggesting that studies with multiple assessments per day may be necessary to detect immediate effects of minority stress. Findings highlight the potential impact of daily experiences of minority stress on alcohol consequences and provide evidence that two general psychological processes may be mechanisms through which minority stress impacts alcohol consequences. These results provide evidence of a need for interventions that teach SMW skills for coping with minority stress and its psychological consequences.