Research in physical education needs to become more multidisciplinary, better integrated with collaborative research in special education, and conducted on large scale. This chapter reviews the research related to motor development and physical fitness in relation to children and youth with intellectual disability, learning disability (LD), emotional disturbance (ED), and autism spectrum disorder (ASD). Research shows 13% to 50% of children with learning disabilities have motor deficits. Most research related to motor performance in children with learning disabilities has focused on confirming and then specifying these delays. There were very few studies that examined motor delays or physical activity issues in children with ED. Most of the research focused on the use of physical activity, sport and recreation on improving self-concept, behaviors and attitudes towards physical activity. In order to best understand how to assist individuals with ASD to improve motor skills and overall fitness, it is important to understand how motor development occurs across the life span of individuals.