The purpose of this study was to expand on research by evaluating the effects of response interruption redirection and response cost alone to reduce vocal stereotypy and to evaluate whether response cost increases the effectiveness of response interruption redirection. Treatment phases included response interruption redirection, response cost, and response interruption redirection plus response cost. We saw high rates of vocal stereotypy during baseline, toy baseline, and pre-intervention phases. During all treatment phases, we saw substantial decreases in stereotypy. For two of the three participants response interruption redirection and response cost was a slightly more effective treatment suggesting that using response interruption redirection with an additive of response cost may further suppress stereotypy. These results were replicated across phases. For one participant response interruption redirection was the most effective treatment. All three treatments reduced vocal stereotypy to clinically acceptable levels for two participants. For one participant, there was only a slight decrease in stereotypy when RC was implemented. We discuss limitations and areas for future research.