Research Findings: The present study concerns children's behavioral adjustment in the context of pre-primary schools in Tanzania. Twenty teachers and 320 children from 20 pre-primary schools participated in the study. Teacher-child relationships, children's behavioral adjustment, and teachers' cultural beliefs were reported by teachers; classroom emotional support was measured through classroom observation. The multilevel findings revealed that high-quality teacher-child relationships and high-quality teacher sensitivity were related to children's prosocial behavioral adjustment. In contrast, observed low-quality teacher-child relationships and low-quality teacher sensitivity were found to be related to children's aggression and anxiety. In addition, teachers' cultural beliefs, concerning play in particular, were found to be related to children's anxiety. The findings support the ecological theory regarding the importance of child characteristics and classroom context in shaping a child's behavioral adjustment in schools. Practice or Policy: The results have implications for pre-primary school teachers in Tanzania, to consider their relationships with children and their sensitivity to children as important aspects for children's behavioral adjustment in schools. They also inform policymakers about the role of pre-primary school teachers in the country.