Research Findings: This study explored the role Head Start teachers' (n = 355) depressive symptoms play in their interactions with children and in children's (n = 2,203) social-emotional development, specifically changes in children's problem behaviors and social skills as reported by parents and teachers during the preschool year. Results of the multilevel path analyses revealed that children in classrooms with more depressed teachers made significantly fewer gains in social-emotional skills as reported by both teachers and parents. We found no evidence of mediation by the quality of teacher--child interactions. Practice or Policy: These findings have implications for understanding and supporting Head Start teachers' mental health and potentially improving children's social-emotional outcomes.