This study examined changes in pupils' agency beliefs and control expectancy from grade four to grade six, and whether they were associated with studying in a class with a special emphasis on a subject as compared to studying in a class without emphasis. After controlling for the effects of mother's education, prior school achievement, and gender, we found that the average pattern of change varied for different action-control beliefs, and that class membership did not moderate these changes. Mother's education, pupils' prior school achievement, and gender all predicted class membership, but their effects on action-control beliefs varied depending on the type of belief. Implications for educational policy will be discussed.