Every teacher, principal, and school administrator wants their young students to thrive as they move through the transitional kindergarten and kindergarten years and into the early elementary grades. With the implementation of the Common Core State Standards and the Local Control Funding Formula, school districts have new opportunities to strengthen support for young learners. When students' strengths and areas for growth are identified and addressed early in their education, they are better prepared for future success. And when districts and communities broadly understand the readiness trends of students entering kindergarten, they can plan and allocate resources to ensure children are supported as early as possible. The statewide use of a uniform, valid, and reliable readiness assessment tool that measures children's learning and development holistically also provides the state with a meaningful way to gauge the diverse and changing needs of its youngest learners. State leaders need this information to better inform early childhood and K-12 planning and resource allocation, as well as to assess the impact of early learning investments and school readiness trends over time. Over half of the states (29) in the country collect kindergarten readiness information in a state-level data system, but unfortunately California is not one of them. There are promising readiness assessment tools that can be used for statewide purposes. However, successful statewide implementation of a readiness tool will require local- and state-level resources and support, as well as leadership, to build momentum among local educational leaders and other key stakeholders across the state. Therefore, policymakers must also play a role in moving California towards a universal, school readiness assessment system that provides uniform data on our state's youngest learners to support their future success by guiding smart and efficient policies at the state level and teaching practices in the classroom.