In this article, we describe how the Virginia Kindergarten Readiness Program, a unique research-practice partnership between the Center for Advanced Study of Teaching and Learning at the University of Virginia, Elevate Early Education (an issue-based advocacy group), and the Virginia Department of Education, was developed to answer a key question: how best to assess the readiness skills of incoming Virginia kindergartners. Across the country, departments of education are recognizing the need to understand how children are entering kindergarten and to define the readiness gap between children from low-income backgrounds and their higher-income peers. In recent years, many states have established comprehensive assessment tools as the first step toward understanding children’s readiness on a larger scale. These assessments help teachers, school divisions (Virginia’s term for districts), and policy makers, and they may be used in a variety of ways depending on the breadth and depth of the data they produce. (author abstract)