Students experience schools through their classrooms and their teachers. The ability of a teacher to motivate students and facilitate learning affects each student’s educational attainment, perhaps more than any other single characteristic of schooling. A large body of research generated over the last 50-60 years has improved our understanding of who teachers are, how they make decisions on whether to teach and where to teach, and how these factors ultimately impact students. This chapter reviews the evidence on teacher labor markets. It asks what factors influence the career decisions then affect the overall teacher workforce, the distribution of teachers across schools, and students’ educational opportunities.