Physical inactivity is a growing international public health concern (World Health Organization, 2018). The need to address physical inactivity is particularly important for children and adolescents with intellectual disabilities, who participate in low levels of physical activity and are significantly less active than their typically developing peers (Boddy, Downs, Knowles, & Fairclough, 2015; Einarsson et al., 2015). These low levels of physical activity are insufficient to gain the clinically meaningful physical and mental health benefits associated with physical activity (Ahn & Fedewa, 2011; Biddle & Asare, 2011; Janssen & LeBlanc, 2010). Since children and adolescents with intellectual disabilities have various chronic health conditions and experience significant health inequalities, such as an increased prevalence of anxiety and obesity and reduced cardiorespiratory and muscular function, promoting physical activity is therefore essential to improve the health of this population (Maiano, 2010; Oeseburg, Dijkstra, Groothoff, Reijneveld, & Jansen, 2011). Children and adolescents with intellectual disabilities, however, face numerous barriers to being physically active. The socioecological model provides a useful framework for categorizing types of barriers as either intrapersonal, interpersonal, organisational or environmental, and has been used in previous studies which have categorized barriers to physical activity faced by children with intellectual disabilities (Bronfenbrenner, 1979; Must, Phillips, Curtin, & Bandini, 2015). Using this framework, existing research demonstrates that children and adolescents with intellectual disabilities face intrapersonal barriers relating to their disabilities, such as