This paper reviews the literature concerned with the effect of various social systems (e.g., the family and the school) on the growth of social competence in the individual child and makes suggestions for further research. The discussion employs the contemporary view of socialization which emphasizes reciprocal causality (i.e., the reciprocal consequences ensuing each time a child interacts with another individual). The first section deals with research on the major social worlds of the child--family, peers, and school--and stresses both how those worlds affect the child and vice versa. For example, the relations between a child's parents will influence the child's social development, but the child's actions also influence the parents' relationship. The second section discusses the interrelationship among the child's social worlds, with a focus on how family relations affect peer relations and vice versa. Considerable use is made of primate studies in arguing that secure family relations have important consequences for peer relations, although the nature of the social interaction differs greatly between the two systems. It is concluded that family relations provide the basis for the child's exploration of the social world which is necessary for social adaptation. Throughout the document, recommendations are made for more detailed empirical analysis of the child's interactions with others and their effects on social development. An extensive bibliography is appended. (Author/BH)