Adults with severe to profound and multiple disability can benefit greatly from creative arts therapies (art, dance, drama, and music therapies). However, it can be very challenging for therapists working with groups to make sure these individuals are fully included. This study is a critical interpretive synthesis using the International Classification of Functioning – it examines what people have written about their work to find ‘facilitators’ and ‘barriers’ in their environment, and explores what these mean for adults with severe to profound and multiple disability and the people supporting them. Although the literature was only from creative arts therapies, it showed a range of ‘Physical’, ‘Social’, and especially ‘Attitudinal’ ‘barriers’, not just in therapy, but also throughout daily life, including ‘Services, Systems, and Policies’. It also showed ‘barriers’ influencing therapists and other support people, which affected the way they worked. These findings strongly suggest wider systemic issues. This paper will help people understand and recognise these ‘barriers’, so that we can change the way adults with severe to profound and multiple disability are perceived and supported, not only for better inclusion in creative arts therapies, but also to advocate for the respect and rights they deserve.