This study investigated the role of level of personality functioning in the relationship between childhood physical abuse (CPA) and traits associated with borderline personality disorder (BPD). While previous research has consistently found a strong connection between CPA and BPD symptoms, the specific psychological processes underlying this relationship are still not fully understood. To investigate this, 654 participants completed three measures: the Childhood Trauma Questionnaire (CTQ), the Level of Personality Functioning Scale - Self-Report (LPFS-SR), and the BPD subscale of the Coolidge Axis II Inventory Plus (CATI+). A simple mediation analysis was conducted to test the role of personality functioning in relationship between CPA and the development of BPD traits. The analysis revealed a significant total effect of CPA on BPD traits (b = 0.371, p < .001). When personality functioning was added to the model as a mediator, CPA significantly predicted personality difficulties (a = 41.024, p < .001), and in turn, personality difficulties significantly predicted BPD traits (b = 0.006, p < .001). Although the direct effect of CPA on BPD traits remained significant, it was notably reduced (c' = 0.107, p = .020). A bootstrap analysis confirmed a significant indirect effect through personality functioning (b = 0.264, 95% CI [0.191, 0.348]). These findings suggest that the pathway from early physical abuse to BPD traits is largely driven by its impact on fundamental aspects of personality. In other words, CPA may not directly cause specific BPD symptoms, but instead fosters broader personality vulnerabilities that predispose an individual to developing BPD traits. These results highlights the importance of addressing core personality functioning in both prevention and treatment efforts for individuals with histories of physical abuse. Effective interventions must address the core disruptions in personality organization, rather than restricting its focus solely to trauma processing or the symptomatic presentation of BPD.