The current study evaluated associations among externalizing psychopathology, personality, and relationship quality in a sample of 794 couples. Personality and psychopathology were assessed using dimensional measures, and relationship attributes were assessed with both self-report and observer reports of videotaped interactions. Results were consistent with prior work (i.e., Humbad, Donnellan, Iacono, & Burt, 2010) such that greater externalizing psychopathology remained a significant predictor of lower relationship adjustment, while controlling for personality traits. Importantly, dimensional measures of externalizing psychopathology showed stronger associations with relationship adjustment when compared to symptom count measures used in Humbad et al. (2010). These results highlight the importance of replication and extension studies, the usefulness of dimensional measures of psychopathology, and the value of multiple methods of assessment to increase confidence in the robustness of associations between pathological attributes of personality and features of romantic relationships.