Recent research has emerged to show increased support for the notion that social-emotional learning (SEL) curricula in schools can improve upon a student’s academic achievement for a number of reasons, so long as the student is actively engaged. There has also been literature support for influence that student-teacher relationships have academic achievement. With these concepts considered, this study investigated the potential mediating effects that student-teacher relationship can have on SEL engagement and academic achievement for math and reading, respectively. Archival data were collected from two low-income, urban middle schools with an established SEL program in place to perform this mediation analysis. Results from the analyses of SEL engagement and academic achievement, student-teacher relationship and academic achievement, SEL engagement and student-teacher relationship, and direct and indirect effects of the mediator were not significant. The implications of these findings for future research and practice, as well as the studies strengths and weaknesses that may have contributed to these results, is discussed.