In mental health and psychiatric care, the use of involuntary psychiatric treatment for people with mental disorders is still a central and contentious issue. The main objective of this scoping review was to map and systematize the literature on ethical issues in clinical decision-making about involuntary psychiatric treatment. Five databases (Embase, PsycINFO, CINAHL, Medline, and Scopus) were searched for articles on this topic. Out of a total of 342 articles found, 35 studies from 14 countries were included based on the selection criteria. The articles were analyzed using the inductive content analysis approach. The following main categories were identified: (1) ethical foundations that guide clinical decision-making; (2) criteria for involuntary psychiatric treatment; (3) gaps, barriers, and risks associated with involuntary psychiatric treatment; (4) strategies used to reduce, replace, and improve the negative impact of involuntary treatment; and (5) evidence-based recommendations. Most of the selected articles discuss the logic underlying involuntary treatment of the mentally ill, exploring ethical principles such as autonomy, beneficence, non-maleficence, or justice, as well as how these should be properly balanced. During the process of involuntary psychiatric admission, there was a notable absence of effective communication and a significant power imbalance that disenfranchised those seeking services. This disparity was further intensified by professionals who often use coercive measures without a clear decision-making rationale and by family members who strongly depend on hospital admission. Due to the pluralistic and polarized nature of opinions regarding legal capacity and the complexity and nuance of involuntary admission, further studies should be context-specific and based on co-production and participatory research.