Li-doped NiO thin films (Li:NiO) were deposited on glass substrates using a facile sol-gel method. The effects of Li doping concentration on the structural, electrical and optical properties of Li:NiO films were examined. The structural properties of Li:NiO films were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy. XRD revealed the Li:NiO films to have a polycrystalline bunsenite structure. The surface morphology of the Li:NiO films exhibited nanocrystalline grains with a randomly oriented morphology. The resistivity decreased substantially to 1.33 k Ω cm at 0.11 mol%, which is one order of magnitude lower than that of the undoped NiO film. The mean transmittance decreased from 70% to 60% with increasing Li doping concentration from 0.02 mol% to 0.19 mol%.