Behavioral inhibition to the unfamiliar is a temperamental construct that refers to a characteristic propensity to react to both social and nonsocial novelty with inhibition. In contrast, shyness refers to feelings of discomfort in social situations but not nonsocial situations. Both shyness and behavioral inhibition are associated with anxiety disorders in children and adults. We compared the role of social and nonsocial inhibition in predicting anxiety disorder symptomatology. Patients (N = 225) at a university affiliated Anxiety Disorders Clinic completed several psychometric measures including the Retrospective Self-Report of Behavioral Inhibition (RSRI) and the Revised Shyness Scale. The RSRI has two replicable factors: social fears and general fearfulness. The social fears factor shows a stronger pattern of relationships to clinically relevant variables such as self-reports of symptomatology, social adjustment, and disability. Social, rather than nonsocial, fearfulness may account for the relationship between behavioral inhibition and anxiety disorder symptomatology.