Of all school-level factors related to student learning and achievement, teachers have consistently been shown to be the most important (Goldhaber 2002; Rockoff 2004; Rivkin, Hanushek, and Kain 2005). Recognizing the importance of teachers to student outcomes, increasing policy attention over the last decade has been paid to improving the quality of our nation’s public school teachers. The No Child Left Behind (NCLB) Act of 2002 introduced school-based accountability on a national scale, and represented the first national effort to set teacher quality benchmarks, requiring states to ensure that all of their teachers were “highly qualified.” Under NCLB, teacher quality was defined by a teacher’s credentials – receipt of a bachelor’s degree, state certification or licensure, and proof of content-area expertise; however, these characteristics have been shown to have a limited relationship with student achievement (Clotfelter et al., 2007; Darling-Hammond & Sykes, 2003; Goldhaber & Brewer, 2000; Goldhaber, 2002; Goldhaber, 2007; Harris and Sass, 2007; Kane et al., 2008). More recently, the federal Race to the Top (RTTT) initiative has emphasized (and provided financial incentives for) systemic reforms to teacher evaluation, focusing attention on the recruitment, development and retention of effective teachers. In doing so, RTTT has led to dramatic changes in how states and local school districts evaluate their teachers. Given both the critical importance of high-quality teachers for all of our nation’s students as well as policy efforts aimed at improving the supply of high-performing teachers, this panel session provides new evidence on a number of factors shaping the teacher labor supply. First, new evidence is presented on how teacher evaluation reform impacts teacher turnover, particularly among the lowest-performing and least-protected (in terms of job security) teachers. Next, new work will demonstrate how accountability pressures influence the distribution of teachers to high-stakes classrooms, and the implications for such strategic teacher assignment are considered. Then, the ways in which multiple dimensions of school context influence student achievement and teacher turnover are considered. Finally, new evidence is presented on how technology influences teacher productivity and the extent of heterogeneity in productivity gains for teachers who vary along the distribution of teacher performance. Together, the work presented in this panel session will offer new insights into how educational policy may be designed to improve the teacher labor supply, and, ultimately student academic performance.