Achieving consensus on the definition and measurement of social competence (SC) for preschool children has proven difficult in the developmental sciences. We tested a hierarchical model in which SC is assumed to be a second-order latent variable by using longitudinal data (N = 345). We also tested the degree to which peer SC at Time 1 predicted changes in positive adjustment from Time 1 to Time 2, based on teacher and peer ratings. Using a multiple-method data-collection strategy, information for three subdomains of SC (social engagement/ motivation, profiles of social interaction and personality assets assessed with Q-sorts, peer acceptance) were collected across consecutive years in preschool programs. Longitudinal confirmatory factor analyses (CFAs) demonstrated invariance of both the measurement and the structural models across age levels and yielded a cross-time path weight of .74 for the second-order factor. Analyses (author abstract)