This study provides psychometric data for a new self-report measure of borderline personality traits from the perspective of the Five-factor model (FFM) of general personality. Subscales were constructed in an undergraduate sample (n = 109) to assess maladaptive variants of 12 FFM traits (e.g., Affective Dysregulation as a maladaptive variant of FFM Vulnerability). On the basis of data from a second undergraduate sample (n = 111), the Five Factor Borderline Inventory (FFBI) subscales were shown to have good internal consistency, convergent, discriminant, and incremental validity. These psychometric results were replicated in a clinical sample of female residents at a substance abuse treatment facility (n = 94).