The authors articulate an expanded dimensional model of personality pathology to better account for symptoms of DSM-defined Cluster A personality disorders. Two hundred forty participants (98 first-degree relatives of probands with schizophrenia or schizoaffective disorder, 92 community control participants, and 50 first-degree relatives of probands with bipolar disorder) completed a dimensional personality pathology questionnaire, a measure of schizotypal characteristics, and Chapman measures of psychosis proneness. Scales from all questionnaires were subjected to an exploratory factor analysis with varimax rotation. A 5-factor structure of personality pathology emerged from the analyses, with Peculiarity forming an additional factor to the common 4-factor structure of personality pathology (consisting of Introversion, Emotional Dysregulation, Antagonism, and Compulsivity). These results support a 5-factor dimensional model of personality pathology that better accounts for phenomena encompassed by the Cluster A personality disorders in DSM-IV-TR (4th ed., text revised; American Psychiatric Association, 2000). This study has implications for the consideration of a dimensional model of personality disorder in DSM-V by offering a more comprehensive structural model that builds on previous work in this area.