The terms peer group and peer cultures most commonly refer to children, preadolescents, and adolescents. In the field of childhood studies, they define children’s groups in relation to social status or age, and who engage in similar activities and share experiences together. For young children, peer cultures involve common cultural activities such as play, verbal genres, and the use of material artifacts as shared affordances for engagement. Preadolescents’ and adolescents’ peer groups and peer cultures are defined in relation to characteristic social practices, behaviors, styles, and consumption patterns. This entry examines the origins of peer cultures, ethnographic research on peer cultures, preadolescent peer cultures, and the differences between multiage or sibling groups and peer cultures.