A lead-free glass series was fabricated according to the chemical formula of (40-x) B2O3+20 TeO2 + (20 + x + y) ZnO + (20 - y) CaO, where x = 0, 2, 4, and 6 mol% and y = 0, 3, 6, and 9 mol%. The role of substitution of ZnO for B2O3 and CaO compounds on the physical and radiation shielding properties of the prepared series was investigated. The density of prepared glasses was examined according to the Archimedes method. The increase in the ZnO across the concentration of 20–35 mol% increases the density of prepared glasses throughout 3.945–4.241 g/cm3. Furthermore, the radiation shielding capacities of the prepared glasses were examined through the experimental measurements using an NaI (Tl) detector and some radioactive sources, including Na-22, Ba-133, Co-60, and Cs-137. The data obtained from the experimental measurements was confirmed using Monte Carlo simulation and XCOM that depend on two various nuclear databases. The experiment, simulation, and XCOM calculations confirmed that the increase in the ZnO concentration throughout 20–35 mol% increases the linear attenuation coefficient throughout 0.352–0.367 cm−1 (at 0.511 MeV), 0.297–0.318 cm−1 (at 0.662 MeV), and 0.210–0.224 cm−1 (at 1.275 MeV), respectively. This increase in the linear attenuation coefficient improves the shielding capacity of prepared glasses, which reach 31.45 % (for the TeZn20 glass), 32.22 % (for the TeZn25 glass), 32.87 % (for the TeZn30 glass), and 33.65 % (for the TeZn35 glass) of the shielding capacity of pure lead at 0.662 MeV.