A substantial literature documents the benefits of early childhood education and formal preschool experiences on children's school readiness, with low-income and otherwise disadvantaged children benefitting the most from these programs. However, these academic benefits often fade out as children age, and most disappear by the end of kindergarten or first grade. The authors suggest one reason for preschool fade-out might be that children's elementary school teachers continue to teach content that children already learned during preschool, thus curtailing academic growth. In this study, the authors investigate two salient approaches available to policymakers that may improve preschool participants' instructional experiences in elementary school: (1) that of advanced and challenging instruction in kindergarten and first grade; and (2) professional support in which preschool teachers interact with their kindergarten and first grade counterparts to develop a seamless transition from one grade to the next. Two experimental studies of preschool interventions (Head Start and Building Blocks) and children's elementary school environments examined whether the quality of instructional content or providing professional development supports to early grade teachers moderate the impacts on children's cognitive skills. Tables are appended.