Attachment insecurities and heightened negative emotions during conflict are significant risk factors for intimate partner violence (IPV). Previous research mainly examined each partner's attachment separately and overlooked negative emotions as a mechanism in the attachment-IPV link. This dyadic observational study conducted among 178 young adult couples examined (1) the interplay between both partners' attachment (i.e., pairings) in association with their IPV perpetration and (2) the contribution of negative emotions during a conflict discussion in these associations. Results revealed that one's avoidance was positively linked with their IPV only when their partner showed low levels of avoidance. One's avoidance was also indirectly associated with their own IPV through their own negative emotions, and to their partner's IPV via their partner's negative emotions. Finally, one's anxiety was indirectly linked with their own IPV through their own negative emotions. Findings support prevention and intervention strategies for IPV that target attachment and negative emotions.