Background Anxiety disorders are highly prevalent disorders associated with substantial psychosocial impairment, but few studies have examined impairment within specific anxiety disorders. Furthermore, it is unclear how change in different types of anxiety has an impact on change in impairment, particularly given high rates of co-morbidity. The current study assessed the temporal associations of impairment and symptoms of three common anxiety disorders in a large, diagnostically heterogeneous clinical sample. Method Data were collected from 606 treatment-seeking individuals at an anxiety clinic, most of whom subsequently enrolled in cognitive-behavioral therapy. Symptoms of panic, social anxiety and generalized anxiety disorder (GAD), as well as levels of impairment, were assessed three times over 2 years. In addition to examining levels of impairment across diagnostic groups, latent growth modeling was used to evaluate the longitudinal associations of anxiety symptoms and impairment. Results Those with a principal diagnosis of GAD reported higher levels of impairment in some domains at baseline; however, at follow-up assessments individuals with social anxiety disorder reported greater impairment than those with panic disorder. Anxiety symptoms and impairment both declined over time. Change in all three anxiety symptoms was closely associated with change in impairment, but only GAD remained a significant (positive) predictor of change in impairment after accounting for co-morbidity. Conclusions Impairment and all three anxiety disorders were closely associated, both cross-sectionally and longitudinally. Because change in GAD was most specifically related to change in impairment, treatment for those with multiple anxiety disorders could focus on treating GAD symptoms first or treating transdiagnostic processes.