<p>This study investigated the mechanical properties of a single crystal of lead tungstate (PbWO₄) through nanoindentation measurements. The Oliver-Pharr method was used to determine the force-dependent Young’s modulus and hardness of PbWO₄. As the applied force increased, the values of hardness and Young’s modulus decreased, which was attributed to the phenomenon known as the indentation size effect (ISE). The force-dependent data was analyzed using the proportional specimen resistance model, leading to a true hardness value of 2.87 GPa. By increasing the applied force from 5 to 100 mN, the Young’s modulus decreased from 82.0 to 71.1 GPa. The observed reduction in Young’s modulus is attributed to the formation of cracks within the material, which likely compromise its elastic response. The study also reported the contributions of plastic and elastic deformation components, revealing that plastic deformation was the dominant one. These results indicate that mechanical properties of PbWO₄ make it a versatile material for technological applications in optoelectronics, photonics, radiation detection and scientific research.</p>