Background. Insomnia and depression often co-occur. Cognitive behavioral therapy for insomnia (CBT-I) seems to be effective and safe for mitigating insomnia and depression. However, the efficacy of digitally-delivered CBT-I (dCBT-I) remains unclear. Therefore, this meta-analysis of randomized controlled trials (RCTs) was to systematically review and evaluate the efficacy of dCBT-I in adults with insomnia and depression.Methods. A systematic search in PubMed, Cochrane, Embase, and Web of Science databases (as of June 5, 2022) was conducted for RCTs on dCBT-I. Statistical analyses were performed using Revan Manager. The effects of dCBT-I on insomnia and depression were expressed as standardized mean difference (SMD) with 95% confidence intervals (CIs). Results. Seven studies involving 3,597 participants were included. This meta-analysis showed that dCBT-I reduced the severity of insomnia (SMD = -0.85, 95% CI [-1.00 to -0.69], p < 0.001) and depression (SMD = -0.47, 95% CI [-0.55 to -0.38], p < 0.001) in short terms, and also mitigated the severity of insomnia (SMD = -0.71, 95% CI [-1.00 to -0.44], p < 0.001) and depression (SMD = -0.42, 95% CI [-0.68 to -0.15], p = 0.002) in long terms. The effect of dCBT-I was comparable to that of traditional face-to-face CBT-I, and was generally maintained at follow-ups of 6 weeks to 6 months.Conclusion. dCBT-I seems to be effective in alleviating insomnia and depression and might be considered as a viable treatment option for depression.