With the growing understanding of the importance of early childhood, leaders in many communities are looking for concrete ideas about how to improve the lives of young children and their families in their communities. They are looking for information and guidance about where to put their resources and energy, how to implement effective programs and services, how to reshape systems to get to more equitable outcomes, and what policy changes will make a difference in families' lives and support early learning. This "Early Learning Community (ELC) Action Guide and Assessment Tool" is designed to support local leaders--from mayors and executive directors to parents and service providers--through a process of assessing how well their community is currently supporting early learning and healthy development, and developing an action plan to make improvements in one or more areas. The tool is built around the four building blocks that make up an Early Learning Community: (1) community leadership, commitment, and public will to make early childhood a priority; (2) quality services that work for all young children and their families; (3) neighborhoods where families can thrive; and (4) policies that support and are responsive to families. Each building block is divided into three to six goals, describing the ideal conditions when that building block is established in a community, and within each goal are three levels that describe how close a community is to reaching the goal. When parents and early childhood leaders from early care and education, health care, and family support services come together to identify actions they can take at the program, neighborhood, or system level to strengthen their communities and support healthy child development, they can make their community a place where all children thrive. Appendices include an at-a-glance overview, an assessment tool scoring sheet, an action planning template, and a glossary and resources. [This paper was created in partnership with the Early Learning Nation Collective.]