The social ability model assumes that normal social relations exist among delinquents, while the social disability model attributes social ineptitude to delinquents. Based on the social ability model, delinquents are expected to have a large proportion of stable, reciprocated choice dyads, high transitivity in triads, and small, distinctive cliques with well defined boundaries. Furthermore, there should be clear status hierarchies in these cliques with discernible leaders and relatively few isolates. Finally, this model suggests that delinquent cliques would be relatively isolated and inaccessible to outside, nondelinquent influences. The social disability model postulates that delinquents lack the interpersonal skills needed to maintain stable, reciprocated relationships. Under this model, delinquents would be expected to have a series of relatively transient and unreciprocated relationships. They would be incapable of managing the complex exchange relations necessary to maintain stable cliques. As a consequence, delinquent cliques would tend to be large and indistinct, with ambiguous hierarchies. Leaders would change often, they would not be very powerful, and their influence would be limited to specific action contexts. These ideal model types require qualification and refinement in order to be applied to specific empirical cases. Actual delinquent groups may exhibit some variations of the peer structures, and external influences may modify actual delinquent peer structures. Tables, 7 notes, and 56 references are provided. (Author abstract modified)