Background <p>WeChat, China's dominant mobile super-application with over one billion active users, offers a uniquely accessible and scalable digital health intervention. Despite a growing body of primary research, no meta-analysis has yet synthesized evidence across all three major diabetes subtypes type 1 (T1DM), type 2 (T2DM), and gestational diabetes mellitus (GDM) for WeChat-based programs.</p> Methods <p>This systematic review and meta-analysis was conducted in accordance with PRISMA 2020 guidelines. Three major databases (PubMed, ClinicalTrials.gov, Cochrane CENTRAL) were searched from inception to 23 April 2026. Eligible studies were selected examining WeChat-based interventions versus usual care in patients with T1DM, T2DM, or GDM, reporting glycemic or cardiometabolic outcomes. The primary outcome was the mean difference (MD) in glycated haemoglobin (HbA1c).</p> Results <p>7 studies encompassing 1,742 participants were included (six RCTs, one quasi-experimental study). WeChat-based interventions produced a statistically significant pooled reduction in HbA1c (MD -1.10%, 95% CI -1.78 to -0.42; I² = 85%; four studies). Fasting blood glucose showed a non-significant directional reduction (MD -0.36 mmol/L, 95% CI -0.76 to 0.03). Two-hour postprandial glucose was significantly reduced (MD -0.21 mmol/L). Diastolic blood pressure was significantly lower in intervention groups (MD -1.59), while systolic blood pressure did not reach significance.</p> Conclusion <p>WeChat-based digital health interventions significantly reduce HbA1c and confer additional benefits on glycemic and cardiometabolic parameters across T1DM, T2DM, and GDM populations. These platforms represent a scalable, low-cost adjunct to conventional diabetes care, especially in Chinese primary health settings. Larger, methodologically rigorous trials with longer follow-up and cost-effectiveness analyses are warranted.</p>