Background <p>People with intellectual disabilities are more vulnerable to environmental stressors and show higher prevalence of psychological disorders. There is little research on interventions specifically for people with intellectual disabilities, although they could offer potential to benefit mental health. Mindfulness and progressive muscle relaxation (PMR) approaches are promising methods. The aim of this study is to evaluate such interventions in people with intellectual disabilities.</p> Methods <p>In a&#xa0;control trial design, two intervention groups and an active control group are compared. This design allows for a&#xa0;comparison between mindfulness intervention, PMR intervention, and control group, as well as a&#xa0;pre–post comparison within the groups. A&#xa0;total of 21&#xa0;participants with mild, moderate, and severe intellectual disabilities took part in the 8‑week training program. Before and after the intervention, the variables relaxation, general worry, and aggression were assessed via interview as self-report and via questionnaire as external report from carers. Furthermore, well-being was assessed at the beginning and at the end of each session. Physiological relaxation was assessed during each session.</p> Results <p>A&#xa0;significant increase in relaxation was observed within the mindfulness and PMR intervention. The PMR, mindfulness, and control group showed a&#xa0;descriptive increase in well-being after the sessions. Further, a&#xa0;descriptive increase in physiological relaxation was found in the mindfulness and PMR group.</p> Conclusion <p>Mindfulness and PMR interventions can be implemented in a&#xa0;group setting in practice to promote relaxation in people with intellectual disabilities. The potential of music interventions has been demonstrated for people with severe intellectual disabilities.</p>