Borderline personality disorder (BPD) is one of the most widely studied personality disorders (PDs). It recurrently shows traits of emotional lability, anxiety, separation insecurity, depressiveness, impulsiveness, risk exposure, and hostility, mainly affecting the domains of negative affectivity and antagonism.To investigate the most discriminant dimensions of the Dimensional Clinical Personality Inventory (Inventário Dimensional Clínico da Personalidade 2 [IDCP-2]) to distinguish people diagnosed with BPD from people without this diagnosis.A total of 305 participants were included in this study: psychiatric outpatients diagnosed with BPD (n = 30), psychiatric outpatients diagnosed with other PDs (n = 75), and a community sample (n = 200). BPD traits were assessed using the dependency, mood instability, and inconsequence dimensions of the IDCP-2.Analysis of variance (ANOVA) comparisons indicated highest mean measures in the BPD group, and mood instability factors were the most discriminant ones when considering all groups. Applying the multiple regression analysis, we found an adjusted r 2 = 0.50, and hopelessness was the most predictive measure (β = 0.32; t = 6.19; p < 0.001).We found discriminatory capacity for factors of all dimensions, although at different levels, and more consistent results to discriminate the BPD group from the community sample.