High-quality summer learning programs in a given city are often only able to address a fraction of the need. Lack of access to program data and absence of stakeholder coordination compounds the problem. Working together to systematically increase program quality and provide more high-quality summer learning opportunities where families need them can lead to improved outcomes for youth. The National Summer Learning Association (NSLA) aids communities that want to build summer learning systems to serve families and youth and has provided extensive support to cities such as Baltimore, Birmingham, Newark, and New York City. NSLA's Community Indicators of Effective Summer Learning Systems, developed in collaboration with community leaders, serve as a road map to building high-quality summer learning systems. Based on systems research, best practices in afterschool and summer system building, and a survey of community intermediaries and program providers, these indicators measure progress in achieving system-building milestones in six key areas including development of a shared vision, engaged leaders, data management, continuous improvement, sustainable resources, and effective communications. These indicators have helped many communities better understand their summer learning needs and strengthen their offerings. With NSLA's support, for example, Newark, New Jersey, leaders convened more than 100 stakeholders, assessed the city's summer learning landscape, identified gaps, and built a common vision for coordinating, expanding, and strengthening high-quality summer learning opportunities for more youth.