Shared Decision-Making (SDM) describes a model of collaborative decision-making that combines the expert knowledge of health professionals and the experiential knowledge of patients. This allows patients to play a more active role in the decision-making process. SDM is also becoming increasingly important in the treatment of persons with mental disorders or cognitive impairments. However, implementation of SDM for this group of patients may face specific challenges, for example, if their decision-making capacity is impaired or if coercion has to be used to prevent acute danger to themselves or others. On the other hand, SDM offers important opportunities in this area. For example, mental health professionals are often more dependent on the patients’ experiential knowledge in clinical decision-making than in somatic care. Furthermore, empowerment and a good therapeutic relationship are central aspects in the treatment of people with mental disorders or cognitive impairments, which can be strengthened by SDM. Against the background of these specific challenges, an overview of opportunities for and experiences with SDM in the care of people with mental disorders or cognitive impairments is given. In addition, different approaches for promoting the implementation of SDM for this patient group will be identified.