Cognitive-behavioral therapy (CBT) has received strong research support for anxiety disorders such as panic disorder, agoraphobia, social anxiety disorder, and generalized anxiety disorder. However, less is known about how CBT performs when delivered in routine clinical care. A systematic review and meta-analysis were conducted of CBT for these anxiety disorders in adults treated in routine clinical care. Ovid MEDLINE, Embase OVID, and PsycINFO were systematically searched for articles published until May 2022. The effectiveness of CBT, methodological quality, and moderators of treatment outcome were examined, and benchmarked by meta-analytically comparing with efficacy studies for the same disorders. Sixty-six studies were included, comprising 6,113 participants. Large within-group effect sizes (ESs; Hedges’s g) were detected for anxiety measures at posttreatment (1.09) and follow-up (1.39), as well as for the secondary outcome of depression measures (0.80 at both assessment points). Attrition rate across the disorders was 15.9%. The benchmarking analysis showed that effectiveness studies had very similar ES (1.09) as efficacy studies (1.07) at posttreatment and at follow-up (1.39 vs. 1.30), and there were no significant differences in remission rates. Thus, the outcomes of effectiveness studies for these anxiety disorders are comparable with the results obtained in efficacy studies.