The purpose of this study is to examine the effect of a Tier II behavior intervention, Check-in/Check-out (CiCo), on student engagement, and if a modification to the intervention that includes teacher use of microaffirmations improves the teacher-student relationship (T-SR) and thus, increases student engagement in class. It utilized multiple baseline design, and the study sample consisted of three fifth grade students from an urban school district in Southeastern Virginia. All three students were paired with one of their teachers to serve as the mentor for the intervention. Student engagement was measured directly using the Behavioral Observation System for Students (BOSS; Shapiro, 2004, and the Inventory of Teacher-Student Relationships (IT-SR: Appendix A; Murray and Zvoch, 2011) was used as a student report measure of the quality of T-SR’s between the mentor and students. Visual inspection was used to analyze the data, and Tau-U (Parker et al., 2011) was calculated to measure effect size. The results of Percent of All Nonoverlapping Data (PAND) analysis found overall small effects in the data from baseline to intervention phases (phi .30). Results of the Tau-U indicated that one student saw no effect (phi .06) and two saw medium to large effect sizes, although one significant effect was for data trending in an undesirable direction (phi .60; -.71). Results on the IT-SR were variable with some increases in the quality of the T-SR, and some reported decreases in the quality of the relationship. This study contributes to the research base by providing a replicable model for implementing an intervention aimed at increasing student engagement with T-SR’s as a moderating factor, as well as for adapting the well-known CiCo program to not only improve student classroom behavior, but also target the T-SR. This study used teacher training on the importance of T-SR’s and the use of microaffirmations with students as an intervention to increase teacher-student relationships, which not only contributes to a methodological gap in the research where discussions about microaffirmations in schools and teacher training is largely conceptual, but it is also easily applied to the school setting where this intervention is intended to be used.