Drawing on resource drain theory, we introduce self-regulatory resource (ego) depletion stemming from family-to-work conflict (FWC) as an alternative theoretical perspective on why supervisors behave abusively toward subordinates. Our two-study examination of a cross-domain antecedent of abusive supervision stands in contrast to prior research, which has focused primarily on work-related factors that influence abusive supervision. Further, our investigation shows how ego depletion is proximally related to abusive supervision. In the first study, conducted at a Fortune 500 company and designed as a lagged survey study, we found that after controlling for alternative theoretical mechanisms, supervisors who experience FWC display more abusive behaviors toward subordinates, and that this relationship was stronger for female supervisors and for supervisors who operate in environments with greater situation-control. These results were then replicated and expanded in an experience sampling study using a multi-organization sample of supervisors. This allowed us to study the FWC-abusive supervision relationship as it emerges on a day-to-day basis and to examine ego depletion as an explanatory mechanism. Consistent with our hypotheses, we found that FWC is associated with abusive supervision, ego depletion acts as a mediator of the FWC-abusive supervision relationship, and that gender and situation-control serve as moderators.