Educable mentally handicapped persons lag well behind nonhandicapped children in the development of both fine and gross movement skills. These persons have difficulty in solving movement problems. Based upon recent work done in cognitive science, it is argued that this lag in movement skill development is related to five major sources: (a) deficiencies in the knowledge base or lack of access to it, (b) lack of spontaneous use of strategies, (c) inadequate metacognitive knowledge and understanding, (d) lack of executive control, and (e) inadequate motivation and practice. A seven-step procedure to teach movement skills to mentally handicapped persons that takes into account these five factors is described. Implications for adapted physical activity are outlined briefly.