Teachers and peers are believed to have a strong influence on student achievement, but the specific characteristics that affect student achievement are hard to identify. This paper utilizes teacher survey data to investigate teacher characteristics that are not usually available in administrative data, as well as more readily available attributes such as experience and education. Classroom fixed effects explain a large portion of within-student variation in test score growth, suggesting a potentially important role for teachers and peers. Teacher characteristics are generally insignificant predictors of student achievement, especially for the lower grades.