The purpose of the current study was to examine how workplace rivalry relates to work-family and wellbeing outcomes. Specifically, informed by resource theory, the relationship of workplace rivalry to work-family conflict was analyzed using a three-timepoint survey of 406 participants (165 with rivals); additionally, the role of psychological detachment as a mediator was tested as were the moderating effects of rivalry intensity and relative standing to one's rival (i.e., perceptions of winning or losing). Results support having a rival is related to greater work-to-family conflict and that the relationship is mediated through psychological detachment. Further, the three-way interaction of rivalry status, rivalry intensity, and relative standing to one's rival was significantly related to both work-to-family conflict and psychological detachment. Notably, the interactions indicated those with intense rivalries they perceived they were losing were particularly vulnerable to undesirable outcomes. Results extend workplace rivalry research and inform on the boundary conditions under which rivalry has negative implications for employee and family wellbeing.