Abstarct: In this experimental research work we have studied the morphological, structural, optical and electrical properties of pure and doped (various Cu at.%) nickel oxide (NiO) samples grown on glass substrate by spray pyrolysis method. We then characterized our samples by using field effect scanning electron microscopy (FESEM), X-ray diffraction (XRD), UV-Vis-NIR spectroscopy, photoluminescence (PL) and Hall effect apparatuses. Here the variable parameters are as following: spray rate (2, 5 and 9 ml/min), substrate type (glass, ITO, FTO), precursor solutions (NiCl2.6H2O, Ni(C2H3O2)2•4H2O), for as-grown and the annealed samples, and finally doping effect. The FESEM images of the samples show a fairly regular formation of the nano-particles and nano-islands on the surface of the substrates. The XRD patterns show all films have a polycrystalline cubic structure mainly oriented along (111) direction. Transmission spectra of the samples indicate that all the grown samples are transparent in the visible range with an indirect band gap of about 3.7-3.9 eV. In Cu-doped samples we found not only the transmittance and optical band gap of laxyers, but also according to the FESEM images the grain size of the nanostructures are also reduced as the doping concentration has increased. The PL spectrum at room temperature in one of these samples indicates the presence of two peaks one in the UV-region (corresponding to near band-edge recombinations) and the other in the visible range the blue region (due to crystalline defect transitions). The electrical measurements also show that the resistivity of the films decreases with increasing the Cu-doping, that means the doping atoms are correctly substitute at the lattice sites in the material. The Hall effect data show that in these samples the carrier densities are around 1015 cm−3.