The topic for this article is parents' participation and willingness to participate in formalized home-school cooperation. The analyses are based on a nationwide survey among parents in lower secondary schools in Norway. A main finding is that parental involvement practices differ according to parents' level of education in the sense that parents with more formal education are more active than less educated parents. Also, the results indicate that parents with low formal education are insecure about their knowledge regarding academic matters, and that this works as a barrier for their participation in formalized home-school cooperation. (Contains 4 tables and 1 footnote.)