© 2017 The Guilford Press. The aim of this prospective study was to expand previously reported evidence on the 10-year clinical and functional course of borderline personality disorder (BPD) in a Spanish sample. Participants diagnosed with BPD were assessed at baseline and at 10-year follow-up to evaluate BPD symptomatology and other relevant clinical measures, suicidal behavior, dimensional personality traits, Axis I and II comorbidity, use of mental health resources, and psychosocial functioning. At the 10-year follow up, significant improvements were observed on BPD domains, suicidal behavior, and other clinical measures. Neuroticism, impulsiveness, and aggressionhostility features trended toward normalization, whereas activity and sociability were impaired over time. Comorbidity with Axis I and personality disorders remained high. Social functioning and occupational functioning were largely unchanged. These findings confirm the tendency toward a symptomatic remission of BPD over the long term with regard to symptom criteria and characteristic dimensional traits. However, psychosocial functioning remains impaired.