Li-doped NiO thin films were deposited on glass and c-axis (0001) sapphire single crystal substrates by radio frequency (RF)-niagnetron sputtering. The effects of the type of substrate, substrate temperature and atmosphere on the structural, electrical and optical properties of the NiO thin films were examined. The electrical conductivity of the NiO thin films depends on the type of substrate, substrate temperature and oxygen atmosphere. The electrical conductivity of the thin films on the glass and sapphire substrates was improved by the introduction of oxygen and decreased with increasing substrate temperature. The optical transmittance decreased with the introduction of oxygen and increased with increasing substrate temperature.