Thin films of zirconium oxide (ZrO2) were deposited on (100) p-silicon and quartz substrates by sputtering of metallic zirconium target under different oxygen partial pressures in the range 8×10−3-6×10−2Pa. The effect of oxygen partial pressure on the structural and optical properties of the deposited films was systematically investigated. The deposition rate of the films decreased from 3.3 to 1.83 nm/min with the increase of oxygen partial pressure from 8×10−3-6×10−2Pa respectively. The X-ray diffraction profiles revealed that the films exhibit (111) refection of zirconium oxide in monoclinic phase. The optical band gap of the films increased from 5.62 to 5.80 eV and refractive index increased from 2.01 to 2.08 with the increase of oxygen partial pressure from 8×10−3-6×10−2Pa respectively.