The purpose of the study was to evaluate the use of a treatment package comprised of a social story, discrimination training, and differential reinforcement with response cost on the vocal stereotypy of one preschooler diagnosed with an autism spectrum disorder. The study took place in a preschool classroom of a public school and was implemented by the classroom teacher and staff. A changing criterion design was employed to evaluate experimental control. The results of this study demonstrated a clear decrease in vocal stereotypy as compared to baseline. (author abstract)