States and school districts across the U.S. are seeking to expand their definition of student success to include social-emotional learning. The CORE Districts, a collaborative of California districts that has developed a system of school accountability and continuous improvement that includes measures of social-emotional skills based on student self-reports, exemplify this trend. In this case study, we provide an overview of CORE's School Quality Improvement System, which was implemented in the 2015–16 school year across six districts serving roughly one million students.