Research has shown both symbolic play and joint attention are delayed and deficient in young children with autism, and predictive of their later language and social development. However, these skills are not often directly addressed in early intervention programs. The proposed treatment study tests an intervention focused on change in play and joint attention interactions between teachers and preschoolers with autism. Specific aims of the study include assessing the degree in which teachers implement the principles and strategies outlined in the treatment, assessing changes in the children's symbolic play and joint attention skills, and exploring teacher and child characteristics affecting optimal treatment outcomes. The methodology includes 16 preschool special education classroom teachers to be randomly assigned to an immediate treatment or a wait-list control group. The treatment utilizes principles of applied behavioral analysis and milieu teaching. Teachers will be observed in the preschool classroom interacting with the children in the classroom in unstructured and structured settings before and after the treatment. During the observations, researchers will code the teacher's implementation of the curriculum as well as the child's joint attention and symbolic play skills. This project advances the state of knowledge in autism by attempting to bridge the gap between research and practice. What this means for people with autism: The absence of social communication abilities in children with autism represents a core area of deficit. Findings from the study will enable researchers to understand the effectiveness of a joint attention training model for teachers of young children with autism and will help determine characteristics that affect treatment outcomes.