Engagement in sociodramatic play has been shown to positively impact young children's learning and development. By definition, this type of social play occurs in groups; however, research to date has primarily sought to understand sociodramatic play engagement by focusing on individual factors. Little work has considered the role of the peer group in sociodramatic play engagement. This concurrent correlational study investigated relations between types of peer group membership and the amount of children's sociodramatic play engagement, using hierarchical cluster analyses, chi-square tests and multiple regression to analyse naturalistic data of preschoolers' free play. Findings suggest that membership in a highly cohesive peer subgroup may be important for sociodramatic play engagement. This study illustrates how social ethological perspectives can be useful for understanding social play in early childhood. © 2021 International Union of Psychological Science.