For adults, developing a stable romantic relationship is often a fundamental life goal, and plays an important role in life satisfaction and overall wellbeing. Conflict is inevitable within ongoing couple relationships, and if not handled appropriately may have lasting negative effects. Hence the purpose of the current study was to examine the impact of attachment insecurities (attachment anxiety and attachment avoidance) on reports of conflict behaviours. Specifically, the research examined the direct associations of attachment anxiety and avoidance with the conflict behaviours of attack, avoidance and problem-solving, together with the indirect (mediating) role of negative partner attributions and the moderating role of relationship quality. Participants (N = 333) completed an online survey in which measures of attachment and relationship quality focused on participants’ current relationship, but items assessing attributions and conflict behaviours were rated with reference to a standardized vignette depicting couple conflict. It was expected that attachment anxiety and avoidance would be associated positively with maladaptive conflict behaviours and negatively with problem-solving. Further, causal and responsibility attributions were expected to mediate the relationships between attachment dimensions and conflict behaviours. As predicted, attachment anxiety was associated positively with attack and negatively with problem-solving, while attachment avoidance predicted conflict avoidance. Attributions acted as a mediator between attachment anxiety and both attacking behaviour and problem-solving, but relationship quality did not moderate the links between attachment insecurities and maladaptive conflict behaviours. This research highlights the important role attributions play in the robust relationship between attachment dimensions and conflict behaviours. Theoretical and practical implications of the research are discussed