This study examined the quality of the classroom climate and dyadic teacher-child relationships as predictors of self-regulation in a sample of socially disadvantaged preschool children (N=206; 52 % boys). Children's self-regulation was observed in preschool at the beginning and at the end of the school year. At the middle of the preschool year, classroom observations of interactions were conducted by trained observers and teachers rated the quality of dyadic teacher-child relationships. Results from multilevel analyses revealed that teacher-child closeness predicted improvements in observed self-regulation skills. Children showed larger gains in self-regulation when they experienced closer teacher-child relationships. Moreover, a moderating effect between classroom instructional quality and observed self-regulation was found such that children with low initial self-regulation skills benefit the most from classrooms with higher classroom quality. Findings have implications for understanding the role of classroom social processes on the development of self-regulation. (author abstract)