This article examines the influence of early development on preschool cognitive and behavioral outcomes in South Africa, as well as the role of family factors such as maternal education in moderating this association. The study involved 167 Black South African children (89 boys and 78 girls) from the Birth to Twenty study during their first 5 years of development. Results indicated that mental development assessed when children were 1 year of age significantly predicted preschool outcomes when children were 5 years of age, over and above the contributions of maternal education. Children with the poorest mental development at 1 year of age also had the poorest cognitive and behavioral development at 5 years of age. However, higher levels of maternal education attenuated the negative impacts of early developmental delay on preschool cognitive and behavioral outcomes. These findings are discussed in light of their implications for early childhood intervention. We conclude that favorable socioeconomic and child care conditions indexed by maternal education compensate for poor infant development.