Background: Borderline personality disorder (BPD) is a debilitating mental illness that affects approximately 6% of the general population and 10–20% of psychiatric patients. The Borderline Symptom List (BSL) is a self-report questionnaire designed to comprehensively assess BPD symptomatology. Sampling and Methods: The present study examined the convergence of the BSL with DSM-IV BPD assessed by semi-structured interview. To ensure variability in BPD symptoms, participants were recruited from a large college sample if they generated either high or low scores on a BPD symptom screening questionnaire. The final sample included 59 participants who completed the BSL, the BPD questions from the Structured Interview for DSM-IV Personality (SIDP-IV), and self-report measures of depression and anxiety. Results: Ten participants (17%) met the full BPD criteria and 29 (49%) met 2 or more criteria. Results indicate strong convergence between the BSL and BPD assessed by semi-structured interview, even when controlling for measures of depression and anxiety. The shortened version of the BSL, the BSL-23, also correlated robustly with BPD assessed by semi-structured interview. Conclusions: Findings support the validity of the BSL (and BSL-23) as a self-report measure of BPD symptomatology. Future research should replicate results in other samples, including those drawn from psychiatric populations.