Deference within a dyad occurs when one partner acknowledges that the other is entitled to some privileges. Although deference is a well-known consequence of relationships between partners of unequal status, little is known on whether deference in one domain can affect interactions between the same actors in the other domains. This can happen within multiplex relationships, especially when they involve firms that have both business and personal interactions between their key decision makers. We combine insights from the literatures on status, multiplex relationships and competitive positioning to examine how actors' behaviors in a business domain of a multiplex relationship are shaped by the deference norms in a personal domain of the same relationship. We argue that marriages between owner-families of Korean business groups cause deferential behaviors between these families as a function of gender-based status differences within kinship ties. We show empirically that the inter-personal deference resulting from marriage affects business group market entries or exits, and in turn the group's performance. Thus, we shed light on how deference spillovers represent a novel mechanism through which one partner can extract advantage over another within a multiplex relationship.