We investigate the effect of neodymium and lanthanum on zirconia radiation shielding and structural properties. To achieve this, new La/Nd-doped ZrO2 nanomaterials were synthesized and analyzed via various experimental techniques, including energy-dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, to determine the fabricated materials' structure, chemical composition, and morphology. Additionally, to enable the estimation of the effect of the ZrO2 phase transition on the synthesized La/Nd-doped ZrO2 nanomaterials' γ-ray shielding properties, Monte Carlo simulation was used. The simulated data revealed that the fabricated materials' linear attenuation coefficient decreased slightly from 17.584 cm−1–17.442 cm−1 at 0.059 MeV, from 0.382 cm−1 to 0.375 cm−1 at 0.662 MeV, from 0.253 cm−1 to 0.248 cm−1 at 1.408 MeV, and from 0.180 cm−1 to 0.176 cm−1 at 15 MeV with decrease of the fraction of the tetragonal phase from 84 % to 57 %. The reduction in the linear attenuation coefficient is associated with increased thickness in terms of the fabricated materials' Pb equivalent and half values.