With the U.S. facing a national teacher shortage that is projected to grow substantially in the coming years, school systems across the country are grappling with the challenge of building and maintaining a high-quality teacher workforce for all students. While school leaders and policymakers might be tempted to solve shortages by focusing solely on teacher recruitment strategies, a better approach begins with understanding teacher attrition and turnover. This report uses data from the most recent nationally representative survey of U.S. teachers (Restricted-Use Schools and Staffing Survey [SASS] 2011-12 and Teacher Follow-Up Survey [TFS] 2012-13) to investigate how turnover trends vary across teachers and schools. Given the significant role turnover plays in teacher shortages, this report discusses turnover trends in major subject areas that commonly suffer shortages--mathematics, science, special education, and English language development--as well as among teachers of color and in high-poverty and high-minority schools. The authors begin with an overview of trends in teacher attrition and turnover, nationally and regionally. The report then looks at these trends by subject area and by teacher and school characteristics. Next, the authors discuss predictors of teacher turnover that have been surfaced in previous research and test them with the most recent national data. The report ends with a discussion of policy considerations, based on research on stemming teacher turnover. [For the research brief see, ED606807.]