Many public school districts are seeking to expand or launch voluntary summer learning programs, especially for children from low-income families. These children experience setbacks over the summer compared to their more affluent peers. Most studies have found that students from low-income families learn less during the summer than do students from higher-income families. Plus, if students do experience summer learning loss, those from low-income neighborhoods experience larger losses over the summer compared to students from wealthier neighborhoods. Voluntary summer learning programs that offer a mix of academics and fun enrichment activities can help address these disparities, potentially helping students from low-income families achieve better academic and social-emotional outcomes. The National Summer Learning Project (NSLP) is the largest study ever to look at whether and how large-scale, voluntary summer learning programs offered by public school districts can help improve educational outcomes for children. The guidance and lessons presented in this guide are based primarily on the experiences of the districts that participated in the NSLP and their partners. The observations and lessons learned by Crosby and the Wallace team, both gained from working closely with each of the districts and monitoring progress of the districts' recruitment efforts, form the foundation for this guide. In addition, focus groups conducted with parents inform much of the discussion about effective messaging presented in this guide. While the lessons learned and the guidance provided here relate directly to public school districts, much of what is offered in the guide may be applicable to other settings, such as community-based organizations that need to effectively engage parents, youth and children to meet their goals and objectives. [This guide was produced in partnership with Crosby Marketing Communications.]