In nearly every state across the country there has been recent legislative or judicial activity aimed at amending policies that shape the quality of the teacher labor force (e.g., Marianno, 2015). At the heart of this recent legislative and judicial action is the desire to attract and retain a high-quality teacher for every classroom. Good policy should be based in empirical evidence of what works to affect change, but what research evidence exists when it comes to improving teacher quality? What new knowledge is needed to inform policy development? Much is known about teachers and schools, but there is still much left to be learned. To move the conversation forward, approximately 50 education experts--researchers, philanthropic leaders, and policymakers--gathered together in May 2016 for two days at a teacher policy conference hosted by the University of Southern California's Rossier School of Education and Policy Analysis for California Education (PACE) with the express purpose of considering what is known and what is left to be learned about the trajectories and career paths of potential and inservice teachers, and how policies can impact the teacher labor force. Discussions covered topics such as the choices that potential teachers face when deciding whether to become educators, the effects of pre-service teacher education, and the career development and advancement of inservice teachers. Attendees focused on what is known about the policies and practices that influence the different parts of the teacher pipeline, and, importantly, where there are key gaps in the empirical evidence. This report synthesizes the main outcomes of the two-day meeting. The authors explain how the meeting was conducted in order to facilitate a consensus of sorts around the most pressing areas for research to inform teacher policy. The report summarizes the main research questions presented in each topic area, and discusses some considerations about the opportunities and challenges presented in engaging in work on these topics. The report concludes with a discussion of cross-cutting considerations for teacher policy research and a call to action.