A Principal’s Guide to Early Learning and the Early Grades primarily focuses on school-based leadership and the roles of elementary school principals. However, leadership, of course, can emanate from state, school district, and community levels. Other practitioners, researchers, policymakers, and advocates are encouraged to use the guide to identify ways to support and collaborate with principals. The guide can also support the design of leadership and professional learning opportunities for principals and shape the activities of principal supervisors. In general, the guide will be useful to any stakeholder interested in improving teaching and learning to ensure every child receives a strong continuum of high[1]quality education across early learning and the early grades. Backed by relevant and recent research findings, the guide defines six competencies to help elementary school principals navigate aligning Pre-K–3rd grade—for children, families, and the adults who serve them within a school—and practical strategies that will support these competencies. The competencies are intentionally related and interdependent. Depending on the school context and current efforts, it may make sense for a principal to begin by focusing on one or two competencies. However, all of the competencies are equally important and necessary to create a unified, coherent leadership approach that supports all young learners. (author abstract)