AimType 1 diabetes mellitus is widely recognized as a chronic autoimmune disease characterized by the pathogenic destruction of beta cells, resulting in the loss of endogenous insulin production. Insulin administration remains the primary therapy for symptomatic treatment. Recent studies showed that disease‐modifying agents, such as anti‐CD3 monoclonal antibodies, have shown promising outcomes in improving the management of the disease. In late 2022, teplizumab received approval from the US Food and Drug Administration (FDA) as the first disease‐modifying agent for the treatment of type 1 diabetes. This review aims to evaluate the clinical evidence regarding the efficacy of anti‐CD3 monoclonal antibodies in the prevention and treatment of type 1 diabetes.MethodsA comprehensive search of PubMed, Google Scholar, Scopus and Cochrane Central Register of Controlled Trials (CENTRAL) was conducted up to December 2022 to identify relevant randomized controlled trials. Meta‐analysis was performed using a random‐effects model, and odds ratios with 95% confidence intervals (CIs) were calculated to quantify the effects. The Cochrane risk of bias tool was employed for quality assessment.ResultsIn total, 11 randomized controlled trials involving 1397 participants (908 participants in the intervention arm, 489 participants in the control arm) were included in this review. The mean age of participants was 15 years, and the mean follow‐up time was 2.04 years. Teplizumab was the most commonly studied intervention. Compared with placebo, anti‐CD3 monoclonal antibody treatment significantly increased the C‐peptide concentration in the area under the curve at shorter timeframes (mean difference = 0.114, 95% CI: 0.069 to 0.159, p = .000). Furthermore, anti‐CD3 monoclonal antibodies significantly reduced the patients' insulin intake across all timeframes (mean difference = −0.123, 95% CI: −0.151 to −0.094, p < .001). However, no significant effect on glycated haemoglobin concentration was observed.ConclusionThe findings of this review suggest that anti‐CD3 monoclonal antibody treatment increases endogenous insulin production and improves the lifestyle of patients by reducing insulin dosage. Future studies should consider the limitations, including sample size, heterogeneity and duration of follow‐up, to validate the generalizability of these findings further.