This study investigates the effect of sintering temperature on structure, ionic conductivity, and dielectric properties of Ce0.8Y0.2O1.9. The lattice parameter, crystallite size, and relative density increase with the sintering temperature. The conductivity and activation energy also has been observed to vary with sintering temperature and show the highest and lowest value respectively at a sintering temperature of 800 °C. Grain boundary thickness exhibits an enlarged value at both low and high sintering temperatures. The samples sintered at high–temperature exhibit lower conductivity and higher activation energy due to the formation of stable defect associates. Sintering temperature affects the dielectric constant of the system. Havriliak–Negami (HN) formalism is used to investigate the effect of sintering temperature on different parameters of dielectric and modulus spectra. Scaling spectra confirms that the conduction, relaxation and reorientation mechanism are sintering temperature independent.