Research on childhood in anthropology and neighboring disciplines has continuously broadened the range of the social partners that are considered relevant for young children’s development—from parents to other caregivers, siblings, and peers. Yet most studies as well as interventions in early childhood still focus exclusively on parents, who are presumed to be the most significant socializing agents. Objecting to such a hierarchical understanding of the social world of children, I propose a complementarity view. Rather than being linearly ranked in a hierarchy of significance, children’s social partners may complement each other by providing different but equally significant experiences. My suggestions are based on an ethnographic study in a rural community in Madagascar. Focusing on children in the first 3 years of life, I explore the full range of their social partners and the respective experiences they provide. Caregivers focus on children’s physical needs and aim to keep them in a calm emotional state, while other young, related children are the most crucial partners when it comes to play, face-to-face interaction, and the exchange of intense emotions. These complementary roles, I argue, lead to the parallel formation of two distinct socio-emotional modes—a hierarchical and an egalitarian one.