This study evaluated whether the positive association between early autonomy-supportive parenting and children's subsequent achievement is mediated by children's executive functions. Using observations of mothers' parenting from the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development (N = 1,306), analyses revealed that mothers' autonomy support over the first 3 years of life predicted enhanced executive functions (i.e., inhibition, delay of gratification, and sustained attention) during the year before kindergarten and academic achievement in elementary and high school even when mothers' warmth and cognitive stimulation, as well as other factors (e.g., children's early general cognitive skills and mothers' educational attainment) were covaried. Mediation analyses demonstrated that over and above other attributes (e.g., temperament), children's executive functions partially accounted for the association between early autonomy-supportive parenting and children's subsequent achievement.