OBJECTIVES: Teprotumumab was approved by the FDA for treating Graves' orbitopathy (GO) in adults on January 21, 2020. This study evaluates its efficacy and safety in treating thyroid eye disease (TED). METHODS: We reviewed studies on teprotumumab for TED treatment from PubMed, Web of Science, EMBASE, Cochrane library, and Clinical trials.gov up to January 1, 2024. Outcomes included proptosis response, diplopia, CAS score, and adverse events (AEs). RESULTS: Our analysis included ten studies, four randomized controlled trials (RCTs), and six observational studies. The RCTs involved 210 teprotumumab patients and 193 controls. Teprotumumab significantly improved proptosis response (RR 4.18, 2.72-6.43), diplopia regression (RR 2.29, 1.54-3.41), and CAS score (RR 3.09, 1.98-4.80) compared to placebo. A significant reduction in proptosis was observed (SMD-8.38, -9.25 - -7.52). The risk of AEs and serious AEs was higher with teprotumumab. The six observational studies included 211 patients, showing an 82% proptosis response rate, a -3.31mm change in proptosis, a 0.58 diplopia improvement rate, and a 0.66 pooled effect size for CAS score. AE incidence was 0.78, and serious AEs were 0.31. CONCLUSIONS: Teprotumumab effectively reduces proptosis, improves diplopia, and lowers disease activity in TED, regardless of previous treatments, severity, or dosage, albeit with increased AEs. It has the potential to become a vital first-line treatment for TED, enhancing patient quality of life.