Based on the emotion socialization and bioecological models, the present study examined the contributions of teacher emotion socialization (i.e., teacher reactions to child emotions) on children’s social–emotional behaviors, and the moderating effect of child temperamental surgency on these relations in the preschool context. A total of 337 children and 80 teachers from private and public preschools/childcares participated in the study. To account for the nested nature of our data, hierarchical linear modeling (HLM) was utilized. The results indicated that several types of teacher reactions to children’s emotions significantly predicted children’s social–emotional behaviors, after adjusting for prior levels of the behaviors. In addition, significant interactions between child surgency and teacher emotion socialization behaviors on children’s social–emotional behaviors were found. These interactions indicated that children with low surgency were more sensitive to teachers’ positive and negative socialization, compared to children with high surgency. Our results highlight the importance of discrete emotion socialization behaviors by teachers to children’s social–emotional development.