Little research has examined teachers' classroom social-emotional practices, including how teachers' warmth and their more explicit emotion socialization practices may be associated with children's social-emotional competencies in different but complementary ways. Likewise, there is scant knowledge on how the effects of the classroom climate may vary by child characteristics. We examined the moderating roles of child gender and temperament in the associations between two aspects of the classroom climate, Head Start teachers' warmth and their explicit emotion socialization practices, and preschoolers' (N = 611) social-emotional competencies, including emotion recognition, self-regulation, and positive social behaviors. While no three-way interactions (teachers' warmth and teachers' emotion socialization practices × child gender × temperament) were significantly associated with outcomes, a two-way interaction between teachers' emotion socialization practices and temperament was significant. Specifically, teachers' emotion socialization practices in the fall were associated with greater self-regulation for all children in the spring, including children with more reactive temperaments although effects were most robust for children with the least reactive temperaments. Implications for teacher practices are discussed. (author abstract)