Environmental education is regarded as a key instrument for promoting pro-environmental behavior in early childhood. In this paper, we analyze the transmission process within a personal value system including knowledge, attitudes, and practices (KAP) regarding the consumption and disposal of plastics among school children, and the extent to which parents play a role in mediating that transmission. The study gathers data from a sample of 1,521 children in southern Chile. Results evidence that the transmission of value systems is a recursive and hierarchical process, where knowledge mediates attitudes, and attitudes (and knowledge) mediate practices. We also find evidence that parents' behavior significantly explains children's behavior in all domains of KAP, with stronger connections among practices where children and parents interact more closely (e.g., packing a lunch box) and in those that are more visible to children (e.g. recycling).