According to a relation-theoretical approach, the construction of reciprocal relationships is an important aspect of social competence. The relevance of intraindividual adaptation of interaction behavior towards different partners for the development of social competence with peers in early childhood has rarely been studied. Three main questions represent the focus of this study: (1) When do children start displaying partner-dependent interaction behavior? (2) When do they develop close reciprocal relationships? (3) Do relationship schemes acquired during early childhood within the peer group predict adaptation to peer groups in kindergarten and school. A longitudinal study was carried out with 13 children in two different age groups (M = 15 months for group A and M = 24 months for group B). Children and their mothers met twice a week in a playroom at a university. Children's interactions were videotaped about 40 minutes weekly and coded. Two follow-ups in the kindergarten and first grade were carried out in order to obtain information about the children's peer status. The Social Relation Model (Kenny & LaVoie, 1984) was applied to analyze peer relationships by differentiating between individual characteristics and partner-specific dependence at the interaction level. The results showed partner-specific dependency for both age groups. However, the dependency as well as close relationships only developed during the second time period within the younger group. Long-term effects of the interaction competence on later peer status in kindergarten and first grade occurred for the younger but not for the older group.