There is increasing interest among educators, policymakers, and researchers in understanding the factors that make some teachers more effective than others, particularly in light of the current focus on educational accountability at the local, state, and national levels. Thus far, only a small body of research exists, however, that links specific teacher qualifications to student achievement. The lack of research is due primarily to the scarcity of data that link student test scores to the characteristics of their teachers. Furthermore, although scholars and policymakers agree that children's early school and family experiences are pivotal, relatively little research exists on the effects of teachers on the educational outcomes of young children. This study fills a gap in the current research base on the relationship among teacher characteristics, instructional practices, and the achievement of young children through an analysis of data from the Early Childhood Longitudinal Study, Kindergarten Class (ECLS-K). The students were assessed in reading and mathematics in both the fall and the spring of their kindergarten year, and detailed information was gathered from their parents, teachers, and school administrators. In particular, the teachers were surveyed with regard to their background qualifications and the instructional practices they use in the classroom. As a result, ECLS-K data may provide information relevant to the relationships between teacher-reported qualifications and instructional practices and student achievement during the kindergarten year.