OBJECTIVE The aim of our study was to examine the association between sleep disturbances and social anxiety disorder (SAD). Another aim was to explore the impact of cognitive behavioral group therapy (CBGT) for SAD on co-occurring sleep difficulties. METHODS Data were obtained retrospectively from patient files receiving CBGT for SAD. The sample included 63 patients with SAD (mean age, 30.42 years [standard deviation, 6.92 years]). There were 41 men and 22 women, of whom 41 participants completed the treatment protocol. Before treatment onset participants completed the Liebowitz Social Anxiety Scale (LSAS), the Beck Depression Inventory (BDI), the Pittsburgh Sleep Quality Index, and several sociodemographic questions. On completion of the treatment protocol, the same measures were completed, with the addition of the Sheehan Disabilities Scale (SDS). RESULTS The results of our study suggest that: (1) subjective insomnia is associated with SAD severity even after controlling for depression severity and additional variables; (2) participants with SAD with co-occurring clinical levels of subjective insomnia present a more severe clinical picture both at treatment onset and termination; and (3) although CBGT lead to reduction in SAD and depression symptoms severity, it had no significant impact on co-occurring sleep difficulties. CONCLUSIONS Sleep difficulties predict SAD severity regardless of depressive symptoms and may be linked to a more severe clinical picture. Clinicians should be aware of these sleep difficulties co-occurring with SAD and consider implementing specific sleep interventions. Future studies should incorporate larger samples sizes from clinical populations outside of Israel.