This research examined how syndromal approaches to assessment can obscure differences between children in the quality of their social interactions. Mixed boys (high for externalizing and internalizing problems) showed heterogeneity in the responses they evoked from others: For one subgroup, aggression and withdrawal evoked aversive responses from others, and even prosocial behavior evoked hostile peer responses; for the other, aggression and withdrawal evoked positive peer responses. Externalizing boys also showed heterogeneity in the patterning of their evoked responses. Within-group heterogeneity was not explained by boys' syndrome scores but was linked to their reactions to specific antecedent events. The results illustrate how a contextualized analysis of behavior can reveal distinctive social interactional patterns that underlie similar overall rates of problem behaviors.