Sol–gel-assisted spin coating technique has been employed to deposit Ce-doped cadmium oxide flms (CdO) thin flms on a glass substrate. Structural analysis carried out by XRD revealed that the flms are polycrystalline and crystallize in a cubic structure. The preferential directions for the CdO growth are (2 0 0), and (2 1 0) and doping of Ce ions inhibits the growth. In addition to XRD, Raman analysis also supports the crystalline phase with no impurities. Using the Kramers–Kronig relations, the dispersion relation is evaluated from which the refractive index and the absorption coefcient were derived. The deposited doped and pure CdO flms are highly transparent. The energy gap values of pure and doped CdO flms are in the range of 2.2–4.2 eV, making them suitable for optoelectronic applications. The lower values of ‘n’ and ‘k’ are making the flms most signifcant. The dielectric constant and nonlinear optical properties showed an increasing tendency on doping Ce ions into CdO flms.