BackgroundIntellectual and developmental disabilities (IDD) comprise lifelong limitations of intellectual, physical, or emotional development. Individuals with IDD face a mean reduction in lifespan of 12·7 years, a 5-times increase in the rate of type 2 diabetes, and a 2-times increase in the rate of cardiovascular disease versus the general public. Exercise can alleviate morbidity and mortality faced by individuals with IDD; however, the barriers to exercise for this population are not well elucidated. We aimed to understand the global variations in barriers to exercise for individuals with IDD. MethodsThis retrospective review examined data collected by the Special Olympics Healthy Athletes Program across 193 countries, separated into seven regions, between February, 2007, and January, 2020. We included 5135 participants (aged 0–80 years) with IDD who reported having no regular activity programme. The primary outcome was which of nine barriers to exercise participants reported, totaling 6368 responses. χ2 tests were used to test significance, at p<0·0001. Participants and guardians provided written informed consent and the study was approved by the author's institutional review board. Findings5135 participants were enrolled, with a mean age of 22·9 years (SD 12·9); 1998 (38·9%) were female. 672 participants lived in Africa, 985 in Asia Pacific, 269 in east Asia, 1135 in Europe and Eurasia, 859 in Latin America, 83 in the Middle East and north Africa, and 1132 in North America. The primary outcome had 6368 responses. For each region except the Middle East and north Africa (p=0·002), there was statistically significant variation in the frequency of reported barriers (all p<0·0001). In east Asia, Europe and Eurasia, and North America, the most frequently cited barrier to exercise was no interest (48·3%, 44·6%, and 56·4% respectively; all p<0·0001). By contrast, no exercise facilities was the most frequently cited barrier in Africa, Asia Pacific, and Latin America (25·1%, 74·9%, and 26·0% respectively; all p<0·0001). For all nine barriers there was regional variation in the frequency each barrier was cited (all p<0·0001). No interest was most often cited as a barrier in North America (56·4%), no exercise person to help in east Asia (11·8%), no equipment or clothes in Africa (5·2%), no person to exercise with in east Asia (9·2%), no transportation in Africa (22·1%), no money in Africa (23·5%), no exercise facilities in Asia Pacific (74·9%), and not safe in Latin America (3·6%). InterpretationBarriers to exercise for individuals with IDD vary depending on the region of the world. Although there are limitations to self-reported data and retrospective review, to our knowledge this is the largest study examining barriers to exercise for individuals with IDD to date. This analysis could help to inform health policy and target interventions to the needs of specific IDD communities to mitigate the effects of their disabilities on chronic conditions and mortality. FundingNone.