In the current paper, glass samples were prepared from the composition xGd2O3–(30-x)Y2O3–70B2O3 (where x = 5, 10, 15, 20 and 25 mol%) via the technique of melt-quenching. Various optical parameters and inter-atomic separation were evaluated for the fabricated samples. The results showed that the inter-substitution of Y2O3 content in replacement with Gd2O3 content in the glass matrix shows structural variation in the glass. The density increases from 3.5521 to 4.1613 g/cm3 with increase in Gd2O3 content that signifies the role of Gd2O3 being a glass modifier. The transmission spectra of the glass sample show more than 85% transmittance suggesting their superior transparency in the visible region. Also, several important shielding parameters of the prepared glass system have been computationally determined via the Geant4 model and the results were compared with Phy-X/PDS database software. The results revealed that the mass attenuation factor (µ/ρ) obtained by utilizing the two different toolkits are in agreement. The transmission fraction and the half value layer parameters of the glass system indicate that the glass sample with higher Gd concentration provides a better gamma blocking ability thanks to the high atomic number of Gd.