Without changes in current policies, U.S. teacher shortages are projected to grow in the coming years. Teacher turnover is an important source of these shortages. About 8% of teachers leave the profession each year, two-thirds of them for reasons other than retirement. Another 8% shift to different schools each year. In addition to aggravating teacher shortages, high turnover rates lower student achievement and are costly for schools. This brief examines turnover trends and causes. It concludes that policies to stem teacher turnover should target compensation, teacher preparation and support, and teaching conditions. [For the full report, see ED606805.]