<p>The present study investigates the effect of Eu³⁺ and Tb³⁺ on electrical and relaxation behaviour of Gd₃Ce₂Al₃O₁₂ (GCAG) garnet at 30&#xa0;°C. The phase analysis and oxidation state of the synthesized ceramics were verified by using XRD and XPS while morphological studies and chemical bonding analysis was performed using FESEM and FTIR. Notably, for 0.5% doping concentration shows decreased activation energy and increased DC conductivity, where Eu³⁺:GCAG shows a peak dielectric constant of 30.15 and DC conductivity of 7.12 × 10⁻⁵ S·cm⁻¹, and Tb³⁺:GCAG reached 27.86 and 5.94 × 10⁻⁵ S·cm⁻¹, respectively. The space charge polarization at grain boundaries was considered to be the cause of the increase in dielectric constant (ε′). The relaxation process displayed a wide range of relaxation time. The relaxation peaks shifted to higher frequencies confirming reduced relaxation time. Furthermore, Activation energies decreased from 0.65&#xa0;eV (undoped) to 0.47–0.55&#xa0;eV (Tb³⁺) and 0.52–0.56&#xa0;eV (Eu³⁺) at 0.5% doping with enhanced DC conductivity.Overall, Tb³⁺ and Eu³⁺ doping has tuned the dielectric properties by offering insights into the defect-mediated conduction in GCAG ceramics as a room temperature dielectric material suggesting its possible suitability for capacitive energy storage applications.</p>