This study empirically examined the effects of the home environment and the moderating effects of preschool teachers' self-efficacy on child development. We utilized the fifth wave of the Korean Children Panel Study(KCPS) data including 1,703 families with 4-year-old children. Multiple regression analyses were used for the data analyses. The results of this study were as follows. First, the higher HOME scores were related to positive impacts on cognitive development, language development, and problem behavior of the children. Also, the higher scores of teachers' self-efficacy had positive effects only on cognitive development. Second, the effects of the home environment on child development were different according to the levels of teachers' self-efficacy as a moderator variable. Teachers with higher self-efficacy significantly elevated children's cognitive development and language development; and decreased problem behavior, regardless of the quality of home environment. It confirms that positive teachers' self-efficacy is a protective factor against negative early childhood development. In sum, the findings of this study prove that the home environment is a significant factor influencing early childhood development. It stresses that practitioners should carefully assess children's home environment in the early stage, and place children living in low quality of the home environment in high-quality child care. Furthermore, training of teachers to strengthen their self-efficacy is one of vital factors to promote the development of children.