Value-added (VA) models measure teacher contributions to student learning and are increasingly employed in educational reform efforts. Using data from 35 seventh-grade teachers and 2,026 students across seven schools, we employ VA methods to measure teacher contributions to students’ motivational orientations (mastery and performance achievement goals) and their mathematics performance. The analysis suggests less variation in teachers’ contributions to students’ achievement goals than mathematics achievement. However, during a time when most students’ mastery motivation is declining sharply, a one standard deviation increase in teacher contributions to student mastery orientation is associated with a 40% smaller decline in student mastery goals. Teacher mastery contributions are also associated with gains in a student’s seventh-grade mathematics achievement (d = .11). In addition to using VA measures to focus on improving student achievement, these measures can be used to orient teachers, schools, and districts on the enhancement of students’ motivation to learn.