In the DSM-IV, social phobia has been subdivided into a generalized and a non-generalized subtype. Although a number of important quantitative distinctions have been identified between the subtypes, most studies have failed to find support for qualitative differences between them. The goal of the present study was to determine whether the investigation of interpersonal problems in social phobia would lead to qualitatively different subgroups, subgroups that would provide additional nonoverlapping information to the DSM-IV classification. Thirty generalized socially phobic, 30 nongeneralized socially phobic, and 30 nondisordered control participants were selected based on dual structured interviews. All participants completed the Inventory of Interpersonal Problems Circumplex Scales (HPC; Alden, Wiggins, & Pincus, 1990). Results showed that when social phobia subtypes were classified using the DSM-IV definition, the IIP-C reflected subgroup differences in global severity of interpersonal problems, with the generalized social phobia group evidencing the greatest difficulty. However, the subgroups could not be discriminated on core or central interpersonal problems. In contrast, when an interpersonal analysis of subtype classification was employed, two groups were formed, each with discriminating core unifying features suggesting qualitatively different problematic reactions to interpersonal situations. One group evidenced interpersonal problems related to hostile, angry behavior, whereas the other group exhibited problems related to friendly-submissive behavior. Interpersonally derived subtypes were unrelated to DSM-IV defined subtypes, depression, and Axis I or avoidant personality disorder comorbidity. The potential clinical relevance of an assessment of interpersonal dysfunction to the treatment of social phobia is discussed.