Since Congress enacted the Elementary and Secondary Education Act in 1965, the federal government has emphasized states' shared responsibility for improving student achievement. When Congress reauthorized the Elementary and Secondary Education Act in 2001 as the No Child Left Behind Act, it called upon states to provide technical support to schools. Specifically, Congress asked states' education agencies to organize "school support teams" to work closely with school and district staff on school improvement. In theory, the task of support teams is straightforward: Improve the performance of districts and schools. But there is nothing simple about what support teams do. This issue brief explores one part of states' work for school improvement--specifically, how state support teams have improved school performance. This brief also considers what issues school leaders face and how these support teams have attempted to help schools meet these challenges. The brief includes some examples of support teams that have changed the ways district and school leaders do their work, but their impact to date on student achievement has been limited. It also explores three themes that emerged in this examination of support teams: (1) State support-team effectiveness varies widely; (2) State support teams in their current form may have done little to improve student achievement; and (3) State support teams, if they are to become a more effective reform strategy, may require some redesign.