This study examined the influence of kindergarten teachers' orientations toward student-centered teaching and their influence on their students' understanding of addition. The study examined 120 students across 10 classrooms. Based on an interview and two classroom observations, 10 teachers were classified as either student centered or mainly teacher centered. Twelve students in each classroom--four above grade level, four at grade level, and four below grade level--were given a task-based interview focused on their understanding of addition. Inductive analysis suggests that students in both types of classrooms could complete addition problems correctly, but students in student-centered classrooms scored better on tasks that involved writing story problems and tasks that involved missing addends. Implications for future research are also discussed.