<p>Mentalization-Based Therapy for adolescents (MBT-A) has been shown to be effective in reducing personality pathology following acute treatment, but less is known about the long-term effects of MBT-A and whether benefits are sustained. This study used a multi-informant, multi-domain approach to examine outcomes up to 2-years post-discharge for 118 young people completing MBT-A who attended an inpatient programme at a Centre for Child and Adolescent Psychiatry Triversum, The Netherlands. Outcome measures included personality pathology dimensions, health-related quality of life and general psychiatric symptoms. Findings revealed that improvements reported post-treatment were maintained up to 2-years post-discharge in many domains. Clinically meaningful changes in measures were also maintained, with benefits observed in areas including self-harm, affective instability, emotion dysregulation as well as quality of life and symptoms of depression and anxiety. These results suggest that MBT-A is effective in providing long-term gains for adolescents with personality pathology. Replication of this study in further clinical settings and with an appropriate control group is needed to further demonstrate the long-term effectiveness of MBT-A.</p>