This study investigated social perspective coordination (SPC) in youth (15-24-year-olds) with first-presentation borderline personality disorder (BPD). SPC is defined as the capacity to differentiate and integrate the perspective of the self with the perspectives of others (Selman, Beardslee, Schultz, Krupa, & Podorefsky, 1986). Two groups: patients with full or sub-syndromal BPD (n = 30) and patients with major depressive disorder (MDD; n = 30) completed measures of SPC derived from the interpersonal negotiation strategies (INS) model (Selman et al., 1986). Compared with the MDD group, the BPD group responded to all vignettes with significantly lower SPC scores and SPC was a significant predictor of BPD status over and above self-reported, personality factors (Neuroticism and Agreeableness), attachment disturbance and functional impairment. These findings suggest that disturbances in social cognition are an important characteristic of individuals with BPD pathology. These difficulties extended beyond attachment contexts and were not limited to situations involving BPD-related themes of abandonment, deprivations or mistrust/abuse.