<p>This study investigates the variations in lithospheric mechanical strength of the Iranian Plateau by integrating flexural analysis theory with gravity anomalies and topographic data, employing Bouguer admittance, correlation analysis, and Bayesian inversion methods. The results show that the effective elastic thickness (<i>T</i>_e) of the Iranian Plateau range from 0 to 65 km, exhibiting significant regional variations. High <i>T</i>_e values are primarily concentrated in the Zagros Orogenic Belt and the South Caspian Basin, reflecting stronger lithospheric strength in these regions. In contrast, lower <i>T</i>_e values are observed in central and eastern areas, particularly around the Lut Block, associated with lithospheric thinning and mantle-derived magmatic activity. Tectonic activity, heat flow, and shear-wave velocity show a close relationship with <i>T</i>_e: regions with high heat flow typically exhibit lower <i>T</i>_e values, indicating weaker lithospheric strength, while Shear-wave velocity is positively correlated with <i>T</i>_e, with higher velocities corresponding to stronger lithospheric mechanical strength. These findings provide essential insights into the crustal structure and lithospheric mechanical properties of the Iranian Plateau and comparable regions.</p>