Background <p>Metabolic syndrome (MetS) is a common metabolic and endocrine disease, and many studies have found that thyroid disorders, both overt and subclinical, might be accompanied by the risk of MetS.</p> Objectives <p>Assessment of indices of sensitivity to thyroid hormones (TH) in euthyroid patients with MetS, and correlation with components of MetS.</p> Patients and methods <p>This cross-sectional study included 240 euthyroid patients with metabolic syndrome living in New Damietta City. The study was conducted from April 2023 to April 2024. Patients were evaluated regarding age, sex, comorbidities, anthropometric measurements, blood pressure, and insulin resistance (IR) using Homeostatic Model Assessment for IR (HOMA-IR), lipid and thyroid profiles. Then, indices of sensitivity to TH were calculated that included thyroid-stimulating hormone index (TSHI), thyroid-stimulating hormone thyroxine resistance index (TT4RI), thyroid feedback quantile-based index (TFQI), parametric thyroid feedback quantile-based index (PTFQI), and the ratio of free tri-iodothyronine to free thyroxine (FT3/FT4).</p> Results <p>Indices of thyroid hormone sensitivity were higher among patients with MetS. The risk factors of MetS were obesity accounted for (92.1%), DM (77.5%), female gender (75%), and HTN (56.2%). All components of MetS, including increased age, female gender, HTN, DM, elevated BMI, WHR, TC, TG, LDL, and reduced HDL were associated with all indicators of sensitivity to thyroid hormones.</p> Conclusion <p>The study demonstrated a significant relationship between indices of thyroid hormone sensitivity and MetS and its risk factors.</p>