Background <p>Depression during pregnancy and postpartum can severely impact psychological and physical well-being, with significant consequences for the child and family. This systematic review and meta-analysis aimed to evaluate the effectiveness of online interventions during pregnancy in reducing postpartum depressive symptoms and enhancing well-being.</p> Methods <p>Randomized controlled trials (RCTs) published in English involving pregnant women over 18&#xa0;years old who participated in online interventions, with or without the support of a health worker, were included. Studies were required to use validated measures for depression and well-being assessed during pregnancy and postpartum. Exclusion criteria comprised literature reviews, meta-analyses, theses, self-help groups and assessment of symptomatology during the period concurrent with maternity blues. A search was conducted using PubMed and EBSCOhost databases, concluding on July 29, 2024. The risk of bias was assessed using RoB 2.</p> Results <p>Eighteen studies with a total of 9,565 participants met the inclusion criteria. Of these, 38.8% involved clinical populations. Variability was noted in theoretical models, gestational age, professional involvement, and intervention activities. The overall effect size was significant (Cohen’s d = 0.37; 95% CI: 0.08 to 0.66; <i>p</i> = 0.0114) with greater efficacy observed in studies using treatment as usual (TAU) as a control and those incorporating relaxation and physical activity.</p> Discussion <p>Limitations include the absence of standardized protocols and uncertainties regarding long-term efficacy. Although the findings suggest potential effectiveness of online interventions in reducing depressive symptoms, further research is required to address gaps in the existing evidence.</p> Other <p>The study received no funding and was registered in PROSPERO (CRD42023420999).</p>