The effect of Vanadium (V) doping on electronic and optical properties of NiO is discussed. Electronic and optical properties of a 32-atom supercell of V[Formula: see text]Ni[Formula: see text]O [Formula: see text] obtained from first-principles calculations, performed within density functional theory (DFT), using the generalized gradient approximation (GGA) with the Hubbard potential [Formula: see text] were studied and compared to those of a 32-atom supercell of pure NiO. From the electronic structure and complex dielectric function analysis, the V doping causes the reduction of the bandgap by inducing the localized V [Formula: see text] state in the NiO bandgap region, and the first optical transition for V-doped NiO occurs at a lower frequency than the one for the intrinsic NiO. The bandgap shrinkage to about 2 eV makes NiO when doped with V a potential candidate for visible light range application in photocatalytic applications. The resulting effects on refractive index, reflectivity, absorption, optical conductivity and loss function for V-doped NiO are compared to those of pristine NiO.