Both family and school environments are considered important proximal microsystems for young children's social and behavioral development. Numerous studies have reported associations between child-caregiver interactions in both family and school and child outcomes. The benefits of quality child-caregiver interactions across home and classroom contexts to child development may be maximized when positive interactional experiences in the home and classrooms are mutually supportive. Recent research employed multilevel models to examine the association between maternal supportive parenting and preschool children's development of social skills and problem behaviors, as well as the cross-level moderating effects of teachers' emotional support. The study took place in Guangdong province, China. A total of 388 children (M = 4.07, SD = 0.41) from 59 preschool classrooms and their mothers participated in this study. Results indicated that higher supportive parenting was associated with children's gains in social skills and decreases in problem behaviors; teachers' emotional support strengthened the effects of supportive parenting on children's development of social skills, but not for their problem behaviors. These findings revealed the importance of both providing young children supportive parenting at home and quality teacher-child interactions in classrooms, as family and schools work together to optimize children's social development.