In partnership with the Massachusetts Department of Elementary and Secondary Education (ESE), and the Minnesota Department of Education (MDE), researchers at American Institutes for Research and the National Institute on Out-of-School Time at the Wellesley Centers for Women are undertaking a study that explores how high-quality out-of-school time (OST) programs can promote participants’ literacy development and the role social and emotional learning (SEL) may play in supporting the development of literacy-related skills. The study will be undertaken in 21st Century Community Learning Centers (21st CCLCs) funded by ESE and MDE that have a demonstrated capacity and track record of providing high-quality afterschool programming over several years. The proposed study is intended to lay the groundwork for the partnership to conduct a series of methodologically rigorous studies that examine the relationship between program quality, SEL skill development, and a variety of school-related outcomes. Information yielded from these studies will assist ESE and MDE in making decisions on how to further develop and support the 21st CCLC grantees to maximize the achievement of a variety of desired youth outcomes associated with youth development and school success while expanding the evidence base for the merit of continued investment in the 21st CCLC program and OST more broadly.