Background: Clinically, personality disorder (PD) commonly coexists with alcohol use disorder (AUD), although within mainstream mental health services both of these mental disorders are routinely overlooked. Despite a rich literature examining the interactions between AUD and personality functioning, personality traits, and PD, there remains conflicting evidence as to the degree of association and impact of one on the other. Methods: A narrative review and a synthesis of the literature were done. Results: The lifetime prevalence of AUD approaches 50% in some PD populations. The rates of PD in AUD populations are less clear but likely similar. Personality influences outcomes in AUD regardless of whether a categorical personality diagnosis or dimensional trait domain approach is taken. There are, however, no good data to inform clinicians on the impact of AUD on the outcomes of PD. Understanding the extent of this impact is complicated by the multiple tools used for diagnosis (of both PD and AUD) and the statistical methods used. Overall, caution is required in interpreting the data due to the quality of the current literature; however, comorbidity between the two disorders is likely significant and the impact of PD on AUD outcomes is sufficient to require consideration. Conclusions: From a research perspective, better agreement on both diagnoses and outcomes is urgently needed to improve the overall quality of the evidence. Clinically, despite the limitations in the literature, it is unacceptable for PD services to ignore AUD and for AUD services not to screen for PD. Both are likely to have an impact on health and functioning and should be considered in routine reviews. A better conceptualization of the putative mechanisms of this interaction, as well as an understanding of the neurobiology and reasons for the impact on treatment outcomes, will help to move the field forward.