<p>We evaluated the role of dysprosium(III) oxide (Dy₂O₃) on the thermal, mechanical, and gamma-ray shielding properties of a lead-borate-based glass system. A series of six glass samples were fabricated according to the chemical formula 20ZnO + (40-z)B₂O₃ + 40PbO + zDy₂O₃, where z = 0, 1, 2, 3, 4, and 5 wt%, using the melt-quenching method. The thermal properties of the fabricated glasses were measured using a Shimadzu DTG-60H thermal analyzer, with temperatures ranging from 25 to 90°C. Additionally, Fourier-transform infrared (FTIR) analysis was performed using a JASCO FTIR-430 spectrophotometer. The mechanical properties of the investigated glasses were evaluated both analytically and empirically based on the Makishima–Mackenzie model. The elastic moduli and ultrasonic velocities were found to increase with the rising Dy₂O₃ content in the investigated glasses. The Young’s, bulk, shear, and longitudinal moduli exhibited enhancement due to the partial substitution of B–O bonds by stronger Dy–O bonds. Furthermore, the gamma-ray shielding properties showed a slight improvement with the substitution of B₂O₃ by Dy₂O₃. The highest mass attenuation coefficient was achieved at 0.015 MeV, increasing from 55.045 to 59.415 cm² g⁻¹ as the Dy₂O₃ content rose from 0 to 5 wt%.</p>