Empirical findings demonstrate insecure attachment and social cognition deficits play etiological and maintenance roles in some personality disorders. The present study examines the specificity of social cognitive factors and insecure attachment in predicting Borderline (BPD) Personality Disorder versus Avoidant (AVPD) and Antisocial (ASPD) Personality Disorders. Data from a non-clinical adult sample were analyzed using structural equation models to assess the direct relationships between insecure attachment and three forms of personality pathology, as well as the indirect effects through identity diffusion, self-other differentiation, and mentalization as social cognition mediators. Results indicated distinct relationships between insecure attachment and each personality disorder, both directly and as mediated by social cognition factors. Specifically, mentalization mediated anxious and avoidant attachment scores in predicting BPD and identity diffusion mediated anxious and avoidant attachment scores for BPD, ASPD and AVPD models. A unique model for ASPD emerged in that attachment scores were fully mediated in predicting ASPD. Findings indicate social cognition factors account for some of the variance in relationships between insecure attachment dimensions and measures of personality pathology, and that the social cognition contributions vary depending upon the form of personality pathology examined. Implications of these findings for theory, assessment, and treatment are discussed.