Little is known about the effectiveness of treatment programmes for personality disordered adolescents. This study investigates the treatment outcome of Inpatient Psychotherapy for Adolescents (IPA), i.e. an intensive programme for treatment refractory adolescents with personality pathology. In addition, this study examines predictors of treatment outcome. One hundred and nine adolescents admitted for treatment of their personality problems were followed up during their stay in IPA. Axis I and Axis II disorders were measured using semi-structured interviews, and the adolescents completed several questionnaires to measure symptom severity (global indices of distress), personality styles and functioning, and quality of life at both start and 12 months after start of treatment. Patients showed improvement in level of symptom severity, personality functioning and quality of life (d ranging from 0.49 to 0.97). As for level of symptom severity, 29% of the adolescents moved into a normative range of symptom severity. Higher levels of self-criticism significantly predicted poorer outcome in terms of symptom severity. Type of personality disorder did not predict treatment outcome. IPA is a potentially effective treatment programme for (a subgroup of) treatment refractory adolescents with personality pathology. Copyright (c) 2013 John Wiley & Sons, Ltd.