This study drew on theories of evolutionary psychology to explore whether mate value discrepancy (MVD) would be associated with relational uncertainty (and its subconstructs) and if relative mate value (RMV) would moderate these associations, such that they would only be significant for lower value mates. Additionally, this article sought to examine whether relational uncertainty would partially mediate an association between MVD and jealousy, also moderated by RMV. Participants recruited from a large Southwestern university (N = 334) completed a survey containing measures to establish MVD, relational uncertainty, and jealousy. MVD was significantly positively associated with relational uncertainty and each of its subconstructs. Relational uncertainty partially mediated the association between MVD and jealousy, although moderation was not supported in any hypotheses.