This article explores the social and cognitive implications of sibling caregiving among the Zinacantec Maya of Mexico and the Wolof of Senegal. Ethnographic video data of sibling caregiving interactions were collected, focusing on children ages three to 13 years interacting with their two‐year‐old siblings. Sibling relations in both cultures reflect a system of multiage play, the children's sensitivity to age and gender hierarchies, and the older siblings'role as teachers of their younger siblings. Differences in the two groups include more verbal exchanges and wordplay with the two‐year‐old Wolof children and more overt efforts by older Zinacantec siblings to incorporate the two year olds into their group activity. The data indicate an overall pattern of cultural transmission by which older siblings teach younger ones in the context of caring for them. The pattern is nuanced by each group's social organization and rules for social interaction, exhibited in the children's play.