Strong teacher-student relationships have long been considered a foundational aspect of a positive school experience. The aim of the current study was to evaluate the effects of the establish-maintain-restore (EMR) method for improving teacher-student relationships and students' classroom behavior while providing elementary teachers with structured professional development and follow-up support. A matched randomized design with a sample of fourth- and fifth-grade teachers and students was used to investigate whether the EMR method produced significant improvements in teacher-student relationships and student outcomes using hierarchical linear modeling to account for nesting at the classroom level. Results indicated that the EMR method was associated with significant improvements in teacher-reported teacher-student relationships as well as improvements in observed indices of students' classroom behavior (academic engaged time and disruptive behavior). Findings also revealed that teacher-reported changes in teacher-student relationships were significantly associated with moderate changes in student classroom behavior. The implications of this study for school-based universal prevention and directions for future research are discussed.