This study tested Vygotsky’s assumption that sociodramatic play in early childhood contributes importantly to the development of self-regulation. It also explored whether the link between sociodramatic play and self-regulation differs for impulsive and nonimpulsive preschoolers. In a short-term longitudinal design, 51 middle-income 3- and 4-year-olds were observed in their preschool classrooms. Naturalistic observations of total dramatic play, complex sociodramatic (CSD) play, and solitary dramatic play and of self-regulation in two classroom contexts—clean-up periods and group circle time—were gathered at Time 1, in the fall of the school year. To assess development of self-regulation, clean-up and circle time observations were repeated at Time 2, in late winter and early spring. CSD play predicted development of self-regulation during clean-up periods, whereas solitary dramatic play was negatively correlated with improvement in clean-up performance. The CSD play/improved self-regulation relationship was particularly strong for high-impulsive children, nil for low-impulsive children. Findings are consistent with Vygotsky’s theory and suggest that sociodramatic experiences may be especially advantageous for impulsive children, who are behind their peers in self-regulatory development.