Theoretical considerations regarding the significance of early peer interaction for later development suggest that socially withdrawn children may represent an ‘at risk’ population. An analysis of behavioral, cognitive, and motivational correlates of intra-individual differences in social involvement suggests that social involvement should be treated as a multidimensional concept. I conceive social involvement as the result of two opposing motivational tendencies, social approach and social avoidance, which I assume to be largely independent of each other. Application of this approach to interindividual differences results in at least three subgroups of socially withdrawn children (unsociable, shy, and avoidant ones). Results of the Munich Longitudinal Study on the Genesis of Individual Competencies show that socially withdrawn children indeed represent a heterogeneous group. Among preschool and kindergarten children, unsociable, shy, and avoidant children, as well as children characterized by a high rate of constructive solitary activity, appear to differ considerably in various social-cognitive characteristics.