The present observational study used hierarchical linear modeling to examine predictors of children's social and self-regulatory outcomes in first-grade classrooms. Specifically, goals were the following: (1) to explore relations between emotionally supportive teacher-child interactions and children's social behaviors (aggression with peers, exclusion by peers, prosocial behaviors) and self-regulatory skills (behavioral self-control); and (2) to examine whether emotionally supportive teacher-student interactions contributed differentially to social and self-regulatory outcomes for first-graders at risk for school difficulty based on sociodemographic characteristics compared to counterparts with fewer sociodemographic risk characteristics. Participants were 178 students and 36 teachers in seven rural schools. Results indicated higher teacher emotional support related to lower child aggression and higher behavioral self-control. Emotional support was equally important for all children regardless of the number of sociodemographic risk factors. Results provide evidence for the contribution of teacher behaviors to students' social behaviors and self-regulatory skills, and suggest the importance of classroom interactions in children's acquisition of social and emotional competence. Discussion focuses on plausible mechanisms and implications for interventions. (Contains 4 tables.)