Out-of-school time (OST) programs can play an important role in fostering the development of literacy skills among children and youth. To investigate the variety of literacy skill-building strategies OST programs use, researchers from the National Institute on Out-of-School Time examined the practices of 31 programs in Massachusetts. This exploration was part of a larger four-year project (2016-2020) with the American Institutes for Research, in collaboration with the Massachusetts Department of Elementary and Secondary Education and the Minnesota Department of Education, funded by the Charles Stewart Mott Foundation. This study, Quality to Youth Outcomes, followed two cohorts of elementary-aged children during two years of sustained participation in 21st Century Community Learning Center programming at 54 centers in Massachusetts and Minnesota to investigate the relationship between high-quality OST programs and the development of social-emotional and literacy skills. Findings from this larger study are under review and will be reported later in 2022. This article describes a sub-study focused specifically on literacy activities. The authors went beyond the comprehension and vocabulary skills typically measured by elementary-age reading assessments to incorporate writing and speaking skills in their investigation. The resulting compendium of literacy-building strategies can help OST programs consider how to grow intentionally as literacy-rich learning environments.