Educators are faced with a variety of problems while teaching. Among the chief concerns are requirements that teachers demonstrate student learning in classes that range in size from quite small to quite large. The problem is further exacerbated by students in these classes who vary in their ability and in their readiness to learn the content. Specific needs-based instruction might be more effective than conventional instruction which often creates conditions that are best described as “one-size fits all”. Classwide Peer Tutoring (CWPT) provides an alternative to the "one-size fits all" condition by sharing responsibilities for student learning with the students themselves. CWPT has also been promoted as an inclusive strategy. However, despite the strong empirical support for CWPT in education, the promotion of CWPT as a best practice in physical education (PE) method text books and recommendations on using peers to assist in the assessment of learning, there are few studies of CWPT in PE. The purpose of this talk is to present a line of experimental research (i.e., 5 studies) conducted by the authors examining the effects of CWPT on students' performance in physical education classes. Four studies were conducted in an inclusive elementary school setting where typically developing students were included with students with autism. The participants in these studies were K-5 students with and without disabilities. The fifth study took place in a suburban public middle school class, with a sixth grade typically developing students. All five studies employed an A-B-A-B single subject withdrawal design to examine the effect of a CWPT package on the number of total and correct trials of a motor skill performed by the students. Results indicate that in general, participants increased their performance, and performed more trials during the CWPT phase than during the conventional whole group instruction phase. Correct trials only slightly increased during the CWPT interventions. These studies extend the literature by (a) demonstrating the effects of CWPT on student engagement in ecologically valid settings; (b) extending the generality of CWPT to middle school PE and to inclusive elementary PE settings. Future studies in this line of research should examine (a) the effects of CWPT on student's performance of other motor skills, (b) how best to train students, and (c) emphasize students' accountability as part of the CWPT strategy. Keyword(s): adapted physical activity, physical education PK-12, research