Mentalization deficits are part of nearly all severe mental disorders. Especially under attachment related stress, limited and disrupted mentalizing undermines complex integration processes of the self. Thus, the treatment has to focus primarily on the quality of these processes and less on a certain content. Mentalization-Based Treatment is a manualized psychodynamic method which targets the promotion of mentalization. This interactional, process orientated approach entails an active-curious, not-knowing stance and small incremental steps of exploration. MBT achieves excellent and sustainable results in several settings, also in comparison with other structurized and manualized methods. Randomized controlled trials showed significant symptom reduction, enhanced quality of life and cost effectiveness in severe and comorbid borderline personality disorder. Various studies on MBT modifications for several other mental disorders are ongoing.