Online psychological interventions for the treatment of depression are increasing as an alternative to traditional face-to-face psychotherapy.Adaptations of cognitive behavioral therapy for the treatment of depression have been tested, with meta-analyses showing weighted effect sizes ranging from d = 0.40 to 0.56.However, there is less evidence on the effect of adaptations of third-wave behavioral therapies for depression.Accordingly, this study reviews the evidence of online applications of third-wave behavioral therapies for depression.Nine randomized clinical trials were found with a total of 1910 participants.Most of these trials implemented online versions of behavioral activation (BA) and acceptance and commitment therapy (ACT).All studies reported positive effects of third-wave therapies.A meta-analysis was conducted with the 6 studies (N = 1744) that compared an online intervention versus wait-list or treatment as usual conditions.Medium to large effect sizes were found with a weighted effect size of d = 0.61.In conclusion, online adaptations of third-wave therapies seem to be legitimate options for the treatment of depression.