Young children with developmental disabilities (DD) frequently have delays in social play skills. Students with DD may require social skills instruction in order to be successful in playing cooperatively with others. These opportunities to practice social play skills learned from specialized interventions must be available throughout the school day. Providing opportunities for positive social interactions, engagement, and play within a classroom setting allows children to make friendships, engage in higher levels of play, participate with peers in multiple social contexts, and lead to overall school success. The purpose of this study was to answer two research questions. The first question examined the relative effects of Video Modeling Other and Peer-Implemented Pivotal Response Training (VMO-PIPRT) when compared to Video Modeling Other alone (VMO) at increasing the number of social play actions in young children with DD in an inclusive setting. Secondly, the study investigated whether the positive effects of the best treatment generalized to the playground for each participant. An alternating treatments design was used to examine the relative effects of the comparison between the two interventions, VMO-PIPRT versus VMO alone. The VMO and VMO-PIPRT treatments were implemented in an inclusive classroom during child-directed learning centers. Data were collected daily during child-directed learning centers and on the playground. Five young children with DD were selected as research participants in the study and ten peer participants were trained on the PIPRT strategies implemented in the VMO-PIPRT treatment. Results of the study were variable between the two treatments and the participants. Visual analysis of the data suggests VMO-PIPRT was more effective for one participant with DD and the relative effect of VMO-PIPRT generalized to the playground. VMO-PIPRT was found to be minimally effective for a second participant with Autism. VMO alone was more effective for a third participant with DD and minimally effective for a fourth participant with Autism. There was no significant effect on the fifth participant with Autism. Generalization of the relative effects to the playground did not occur for the remaining four participants; however, there were increased levels of social play actions, or positive social interactions, when phases of treatment were compared. Further analysis of initiations suggests the research participants engaged in higher levels of initiations in the classroom and on the playground compared to reciprocal social play actions. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]