U.S. education leaders have spent decades highlighting and attempting to close achievement gaps among demographic groups. The gaps between African-American and Latino students compared to their white and Asian peers, as well as the gaps between low-income students and others, are among the most pernicious. In 2017, Oak Foundation commissioned Public Impact to develop this report as a resource for district leaders nationwide facing such achievement gaps, based on a review of more than 150 studies conducted over a decade. The report reviews the causes of achievement gaps and highlights research-based approaches to closing them. It examines approaches that had evidence of boosting outcomes for disadvantaged students without reducing availability of advanced instruction, for two reasons. First, when all students have help to leap ahead, all will need advanced instruction. Second, schools that serve all students well, regardless of background, build strong family and community support for and commitment to public education. The research reveals that change is possible. Despite a discouraging history, the many efforts have provided researchers with a deep knowledge base about the causes of persistent gaps and approaches that achieve partial progress. The causes are multidimensional, and thus the solutions are as well--tackling the instructional, emotional, and practical needs of students, their families, and the educators who serve them. This report builds on decades of research about what works to present a fresh view: If district leaders and their communities commit to close gaps, act on a combination of research-based approaches to address achievement gaps, engage their communities actively in the effort, and allow themselves to be held accountable for progress, they can equip low-income students and students of color to close gaps and succeed in large numbers. [Writing contributions for this report by Bryan C. Hassel, Emily Ayscue Hassel, Stephanie Dean, and Veronica Brooks-Uy.]