Many students with autism have difficulties engaging with their classroom environments and forming friendships, which are mostly affected by deficits in social, communication, and motor skills. The Special Education Elementary Longitudinal Study (SEELS, 2000) data set was used, focusing on elementary age students with autism, to explore the longitudinal relationships between social, communication, and motor skills and the mediating role of motor skills in between communication and social skills by using structural equational modeling analyses. Results show that (a) motor skills mediate the relationship between communication and social skills in elementary school, (b) there are significant longitudinal relationships among these skills in elementary school. Increased motor skills may improve social skills for students with autism in elementary school.