BACKGROUND: New technologies have made rapid advances in the field of assistive technologies (AT), with Extended Reality (XR) offering promising results in supporting people with mild intellectual disabilities (ID). Yet, the design and goals of programs for people with mild ID may differ from those for people with moderate and severe ID. It remains unclear how XR technologies are used for people with moderate to severe ID. OBJECTIVE: The study we present in this paper aimed to explore what is known from the existing scientific literature about XR-based interventions for supporting people with moderate to severe intellectual disabilities, including the features of XR content and technology that is used and factors that may impact implementation. METHODS: We conducted a scoping review, searching Cinahl, PubMed, LibSearch, and Google Scholar based on inclusion and exclusion criteria ensuring the focus on XR and moderate to severe ID. We adopted a qualitative content analysis approach to review the papers resulting from the search. RESULTS: In total, we included 16 papers in the review. Most of these focused on XR-based interventions to improve specific skills, such as navigation and daily living skills, in order to increase autonomy and independence. We found a large variety in the content and technology used in these interventions as well as in factors that the authors found to affect the implementation. These factors concern characteristics of users, of caregivers or facilitators, and of the XR environments and systems. The majority of the papers reported studies with small sample sizes, and lacked control groups and follow-up periods to measure long-term effects of XR. CONCLUSIONS: The use of XR for people with moderate to severe ID is an emerging field. Although many authors of the reviewed studies do acknowledge the potential of XR, further evidence is needed. Future research might explore the potential of XR as leisure activity, and might study in detail how features of the XR environment impact behaviour to inform professionals about how to approach their use of XR in order to meet the needs and preferences of people with moderate and severe ID.