Social skills training (SST) interventions are evidence-based approaches to building prosocial behavior. When used in schools, SSTs are commonly situated within Multi-tiered Systems of Support (MTSS) as Tier 2 interventions. Despite promising gains in social skills and social understanding from SST participation, criticism is noted that gains do not always generalize to improved social behavior in the classroom setting. Existing literature documents mixed results for improved classroom behavior resulting from social skill development in SSTs. The current study utilizes ANCOVA to examine the effect of SST intervention for classroom behavior, within a sample of peer-rejected students drawn from the larger Friendship Connection Project (FCP) study. Additionally, it was hypothesized a close teacher-student relationship would boost intervention effects for classroom behavior. Students' classroom engagement behavior was measured through teacher-rated Daily Behavior Ratings (DBR). Student DBR did not significantly change because of participation in FCP's intervention group. Further, the teacher-student relationship quality did not moderate the relationship between FCP intervention participation and DBR. Methodological limitations such as restricted room for DBR improvement based on time 1 measurements are discussed. These results underscore the heterogeneity of peer-rejected students in that students in this study did not demonstrate elevated behavioral concerns prior to the FCP intervention. Discussion of results also highlights the importance of specificity of Tier 2 targeted interventions; improvements in social understanding and social behavior may not extend to improvements in disruptive classroom behavior. [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.]