This study examined the extent to which classroom quality (emotional and instructional climate) moderates the associations between teachers' beliefs about children, self-efficacy, and children's early language gains (receptive and expressive vocabulary). The study employed multilevel modeling with 606 preschool teachers and 2,536 preschool children. Results revealed that teachers' beliefs about children were the only teacher construct that was significantly associated with both receptive and expressive vocabulary gains, after accounting for between-classroom effects. Classroom quality showed a positive trend toward significantly predicting residualized change in children's receptive and expressive vocabulary gains.