["Child and Adolescent Mental Health, EarlyView. ", "\n\nBackground\nAnxiety disorders are highly prevalent in childhood and adolescence, but access to treatment is limited. Internet‐based cognitive behavioral therapy (ICBT) has been proposed as an effective treatment to increase accessibility to evidence‐based treatment.\n\n\nObjective\nThis systematic review and meta‐analysis aimed to investigate the efficacy of ICBT for children and adolescents with anxiety disorders and explore moderating effects of control conditions, age, parental involvement, and therapist support on treatment outcomes.\n\n\nMethods\nSystematic searches were conducted in PsycInfo, PubMed, SCOPUS, Embase, and Web of Science to identify randomized controlled trials comparing ICBT with control conditions controlling for the effects of time or nonspecific effects of treatment. Studies should include children and adolescents aged 6–18 years with anxiety disorders.\n\n\nResults\nThe searches identified 1241 papers, of which 11 studies met the inclusion criteria. The adjusted pooled effect size estimate for the random‐effects meta‐analysis demonstrated a medium statistically significant effect in favor of ICBT over control conditions (g = 0.740, 95% CI 0.555–0.925). The overall quality of evidence (GRADE) was rated as low due to risk of bias and inconsistencies in reporting. No significant moderators of treatment effects were identified.\n\n\nConclusion\nThis meta‐analysis supports the use of ICBT as a treatment option for children and adolescents with anxiety disorders. Additionally, the results suggest that therapist support format may be a relevant treatment component to explore in future studies. However, all findings must be subjected to additional testing, and more high‐quality studies including long‐term follow‐ups are needed to assess the effects of ICBT and clarify the impact of moderators.\n\n"]