Seventy patients seeking treatment for social anxiety disorder (SAD) were randomly assigned to 14 weekly individual sessions of interpersonal therapy (IPT) or supportive therapy (ST). We hypothesized that IPT, a psychotherapy with established efficacy for depression and other psychiatric disorders, would lead to greater improvement than ST. Patients in both groups experienced significant improvement from pretreatment to posttreatment. However, improvement with IPT was not superior to improvement with ST. Mean scores on the Liebowitz Social Anxiety Scale decreased from 67.7 to 46.9 in the IPT group and 64.5 to 49.8 in the ST group. There were also no differences in proportion of responders between IPT and ST. Only for a scale measuring concern about negative evaluation (Brief Fear of Negative Evaluation Scale) was IPT superior. Limitations of this initial controlled trial of IPT include a nonsequential recruitment strategy and overlap in the administration of the two therapies. It is recommended that future studies of IPT for SAD include a more carefully defined control therapy condition, different therapists administering each therapy, a larger sample, and a more rigorous strategy for long-term follow-up assessments.