The current meta-analysis reviews research examining the relationships between each of the five-factor model personality dimensions and each of the 10 Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) personality disorder diagnostic categories. Effect sizes representing the relationships between these two constructs were compiled from 15 independent samples. Results were analyzed both within each individual personality disorder category and across personality disorders, indicating how personality disorders are different and similar, respectively, with regard to underlying personality traits. In terms of how personality disorders differ, the results showed that each disorder displays a five-factor model profile that is meaningful and predictable given its unique diagnostic criteria. With regard to their similarities, the findings revealed that the most prominent and consistent personality dimensions underlying a large number of the personality disorders are positive associations with Neuroticism and negative associations with Agreeableness. Extraversion appears to be a more discriminating dimension, as indicated by prominent but directionally variable associations with the personality disorders. The implications of these meta-analytic findings for clinical application and the advancement of future research are discussed.