Objectives: This study aimed to conduct a systematic review of cost-utility studies of internet-based and face-to-face cognitive behavioral therapy (CBT) for depression from childhood to adulthood and to examine their reporting and methodological quality. Methods: A structured search for cost-utility studies concerning CBT for depression was performed in 7 comprehensive databases from their inception to July 2020. Two reviewers independently screened the literature, abstracted data, and assessed quality using the Consolidated Health Economic Evaluation Reporting Standards and Quality of Health Economic Studies checklists. The primary outcome was the incremental cost-effectiveness ratio (ICER) across all studies. To make a relevant comparison of the ICERs across the identified studies, cost data were inflated to the year 2020 and converted into US dollars. Results: Thirty-eight studies were included in this review, of which 26 studies (68%) were deemed of high methodological quality and 12 studies (32%) of fair quality. Despite differences in study designs and settings, the conclusions of most included studies for adult depression were general agreement; they showed that face-to-face CBT monotherapy or combination therapy compared with antidepressants and usual care for adult depression were cost-effective from the societal, health system, or payer perspective (ICER $241 212.4/quality-adjusted life-year [QALY] to $33 032.47/QALY, time horizon 12-60 months). Internet-based CBT regardless of guided or unguided also has a significant cost-effectiveness advantage (ICER $37 717.52/QALY to $73 841.34/QALY, time horizon 3-36 months). In addition, CBT was cost-effective in preventing depression (ICER $23 932.07/QALY to $26 092.02/QALY, time horizon 9-60 months). Nevertheless, the evidence for the cost-effectiveness of CBT for children and adolescents was still ambiguous. Conclusions: Fair or high-quality evidence showed that CBT monotherapy or combination therapy for adult depression was cost-effective; whether CBT-related therapy was cost-effective for children and adolescents depression remains inconclusive.