The structural and dielectric properties of SrBi2−xCexNb2O9 (x = 0, 0.2, 0.35) oxides prepared by a solid state method have been examined. The samples are characterized by means of scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray powder diffraction and Fourier-transform infrared spectroscopy. The results obtained from different experiments correlated well to reveal the structure–property relationship. The impact of cerium substitution on the dielectric properties of the SrBi2-xCexNb2O9 is elucidated. Ce-doped SrBi2Nb2O9 ceramics have low dielectric loss values and the flattening of the dielectric constant at higher frequencies. The dielectric loss decreased for doped compositions compared to SrBi2Nb2O9 at room temperature, whereas the dielectric constant was higher for doped ceramics due the possible incorporation of Ce4+ and Ce3+ ions into the Bi2O2 layers. A significant increase in diffusiveness was observed with increasing Ce.