Purpose: Online group-based interventions are widely adopted, but their efficacy, when compared with similar face-to-face (F2F) psychosocial group interventions, has not been sufficiently examined. Methods: This systematic review included randomly controlled trials (RCTs) that compared an intervention/model delivered in both F2F and online formats. The review adhered to PRISMA guidelines and was registered with PROSPERO. Results: The search yielded 15 RCTs. Effect sizes ranged from small to exceptionally large. Between-condition effect sizes yielded nonsignificant differences in effectiveness except for three studies that reported superior effectiveness in outcomes for F2F interventions. High heterogeneity was found where only two studies integrated rigorous designs, thus limiting opportunity for a meta-analysis evaluation. Conclusions: Most studies showed comparable outcomes in both F2F and online modalities. However, given the heterogeneity of samples and outcomes, it is premature to conclude that online treatment is as effective as F2F for all challenges and populations.