Changes in students’ achievement values in mathematics and reading were examined in a sample of children and early adolescents. Hierarchical linear modeling techniques were used to account for both classroom- and student-level effects. At the student level, positive changes in students’ achievement values were associated positively with self-concept of ability and the previous year’s achievement values in both reading and math. Measures of teachers’ mastery- and performance-oriented instructional practices were included in the full HLM model. Students experienced decrements in achievement values, after controlling for other student and classroom-level variables, in classrooms where performance-oriented instructional practices were used. In the full model, self-concept of ability was related positively to increases in achievement values, whereas gender was unrelated to changes in achievement values.