The aim of this paper is to examine the effect of socio-demographic factors, children’s motor skills and parents’ physical activity on the physical activity of preschool children with intellectual disabilities. The research sample included 47 children with intellectual disabilities, as well as 47 parents. For the examination of socio-demographic variables, a questionnaire was created, which included information about parents and children. The Vineland Adaptive Behavior Scale was used to assess adaptive behaviour in the domain of motor skills. For assessing the children’s gross motor skills, the Test of Gross Motor Development was used, and the Family Lifestyle Survey was used for the assessment of the physical activity of parents, and children with intellectual disabilities. The results show that the majority of children with intellectual disabilities partake in some physical activity for at least 20 minutes, one to four times a week. Multiple linear regression analysis found that the independent variables explained 11.2% of the variance in children’s physical activity. Gross motor skills represented the strongest individual contribution to the physical activity of children with intellectual disabilities.