Children's relationships with teachers in kindergarten are crucial for academic and social success. Research shows that teacher-child relationships are predicated, in part, on children's temperament. The "INSIGHTS into Children's Temperament" intervention was intended to improve children's and teachers' understanding of their and others' temperament, and has been shown to improve children's social skills and self-regulation in urban, under-resourced schools. The current study is part of a replication of the effects of INSIGHTS with a sample in rural schools. The purpose was to test the effectiveness of INSIGHTS for promoting positive relationships between teachers and children in kindergarten. Two cohorts of kindergarten students (N = 127) and teachers (N = 30) were randomized into INSIGHTS or control conditions by school. Teachers reported on the quality of the teacher-child relationship before and after the INSIGHTS intervention (Time 1 and 2) using the Student-Teacher Relationship Scale: Short Form and provided a rating of children's temperament with the Teacher School-Age Temperament Inventory at Time 1. Data were analyzed with hierarchical linear modeling. Two significant findings emerged. First, INSIGHTS promoted more closeness between teachers and children, regardless of temperament. Second, the INSIGHTS intervention was protective against the development of conflictual teacher-child relationships for children with negative reactivity.