How couples communicate during conflict interactions can have important implications for their relational well-being. The theory of resilience and relational load provides a valuable lens for exploring the associations among couples’ language use during conflict conversations and the extent to which such conversations are perceived as threatening to one’s relationship, as well as whether genetic markers moderate such associations. Forty-seven mixed-sex couples had a conversation about a topic causing conflict in their relationship and provided saliva samples that were tested for their genotype (GG, AA, or AG) for oxytocin receptor gene rs53576. The results revealed that neither the use of communal language nor positive emotion words were associated with perceiving the conversation as less threatening to their relationship. Genetic variation did not moderate the associations with either positive emotion word use or communal language. However, a three-way interaction between sex, OXTR, and positive emotion word use emerged in the post hoc analyses, indicating that positive emotion word use was negatively associated with threat appraisals for women with a GG genotype, and positively associated with threat appraisals for men with a GG genotype. Implications for mixed-sex couples’ communication and research on language use during conflict conversations are discussed.