Background: Patients with social anxiety disorder (SAD) report fear content relating to the perceived aversive consequences of their anxiety for others in their social environment. However, no studies to date have examined the diagnostic specificity of these fears to SAD as well as predictors to treatment response of these fears. Aims: To examine relative specificity of fears related to causing discomfort to others, as measured by Social Anxiety–Fear of Causing Discomfort to Others (SA-DOS), among patients with anxiety disorders, obsessive compulsive disorder (OCD) and major depressive disorder (MDD), in addition to relation between dysfunctional attitudes and treatment response among patients with SAD. Method: In study 1, a large (n=745) sample of DSM diagnosed OCD, MDD and anxiety disorder participants completed the SA-DOS. In study 2, patient participants with SAD (n=186) participated in cognitive behavioural group therapy (CBGT) and completed measures of social anxiety symptoms and dysfunctional attitudes. Results: In study 1, the SAD group demonstrated significantly elevated SA-DOS scores compared with participants with generalized anxiety disorder (GAD), OCD and panic disorder with or without agoraphobia (PD/A), but not the MDD group. In study 2, CBGT treatment was found to lead to significant reductions in SA-DOS scores. Need for approval (NFA) but not perfectionism, predicted treatment response to fears related to causing discomfort to others, with greater change in NFA relating to greater change in SA-DOS scores. Conclusions: These findings extend previous research linking allocentric fears to the phenomenology and treatment of SAD.