Abstract: Prior work has shown that students’ reports of their levels of social-emotional skills predict achievement levels and gains, but we have little evidence on whether within-student changes in student reports of social-emotional skills are predictive of changes in theoretically related academic and behavioral outcomes. We use large-scale data from the California CORE districts to examine whether changes in individual students’ reports of their social-emotional skills from one school year to the next predict changes in state math and English language arts (ELA) test scores and attendance. The CORE districts provide the largest yearly measurement of social-emotional learning (SEL), achievement, and attendance data in the U.S. We show that changes in self-reported social-emotional skills predict changes in both achievement and attendance. These results are robust across model specifications. Moreover, the relationships between SEL and achievement and attendance outcomes are consistent across student subgroups.