This study tested a classwide peer tutoring model using rule-governed responding to teach tutors to accurately present learn units during social studies instruction using a multiple baseline across participants with pre and post intervention probes. Three students, aged 8 to 10, in a self-contained 3rd/4th grade CABAS[R] classroom participated in this study to test the effects of peer tutoring on the social interactions of the students during unstructured free time and accurate implementation of learn units during tutoring. The results showed an increase in social approvals and accurate learn unit presentations and a decrease in social disapprovals after the introduction of rule-governed peer tutoring. Additionally, the results showed a classwide (and individual participant) increase in social approvals and a decrease in social disapprovals during unstructured free time. (Contains 5 figures and 1 table.)