State policymakers have worked hard to increase prekindergarten enrollment and ease young children's transition to kindergarten, and with good reason. There is abundant evidence that attending a formal preschool program such as state pre-K or Head Start boosts students' academic and social competencies significantly and meaningfully, regardless of race or linguistic or cultural background, and particularly for those in low-income homes. However, the skill boosts for pre-K attenders, relative to those of nonattenders, diminish over the kindergarten year by more than half. That is, students who attend pre-K outperform their peers at first, but nonattending students catch up. This article discusses how better alignment in policy and practice can ensure that the skill boosts from pre-K persist throughout the elementary years.