Social and emotional learning (SEL) is the process through which students develop such interpersonal and intrapersonal competencies as teamwork, social awareness, self-regulation, and emotional awareness. Although schools in the United States have always addressed these competencies, in recent years, the availability of resources to address SEL has expanded, and educators are increasingly adopting SEL-focused curricula, practices, and assessments in their classrooms and schools. This report presents findings from nationally representative samples of teachers and principals surveyed for the RAND Corporation's web-based American Educator Panels; these educators responded to questions addressing their beliefs about the importance and value of SEL in schools, their approaches to promoting and measuring SEL, and their opinions regarding supports for improving SEL. The findings should be useful to developers of SEL-related resources such as curricula, assessments, and training programs, and to researchers, policymakers, and practitioners who are interested in understanding what kinds of supports and resources educators need. [For the appendixes, see ED609686.]