Based on promising preliminary results from clinical trials, it seems likely that psychedelic substances (classic serotonergic psychedelics, such as psilocybin, and entactogens, such as MDMA) will be introduced into psychiatry as psychedelic-assisted therapy. This also raises a range of ethical questions that urgently need to be addressed before widespread roll-out in society. This scoping review fills a gap in the literature by providing an overview of these ethical issues using a systematic search, presentation, and descriptive analysis of ethical issues in psychedelic-assisted treatments. It includes peer-reviewed studies pertaining to human study participants and psychiatric patients (population), which discuss ethical issues (concept) of psychedelic treatments (context) in clinical trials and other clinical applications. The systematic search included several databases: MEDLINE, PsycInfo, CINAHL, HeinOnline, and PsycArticles. The search strategy, including all identified keywords and index terms, was adapted for each included database. The search was completed in June 2025 and studies published until then in any language were included. After an iterative process of inductive and deductive coding of ethical issues, the scoping review comprises seven themes related to the ethics of psychedelic-assisted treatments: (1) safety and patient well-being, (2) therapeutic relationships, (3) informed consent, (4) equity and access, (5) research ethics, (6) special contexts, and (7) societal and cultural implications. The results can be used to inform and stimulate further discussion and in-depth research on the ethics of psychedelic-assisted treatments, possibly leading to more nuanced debate surrounding a safer and more ethical implementation of psychedelic-assisted treatments in the future.