Abstract: Undoped and W-doped zinc oxide thin films were prepared on quartz substrates by sol-gel process. The effects of tungsten doping on the structure and optical properties of ZnO thin films were investigated. The results suggested that the crystalline quality of ZnO thin films was improved with the doping of tungsten and the peak position was shifted to the lower diffraction angles. The optical band edge of W-doped films showed a red-shift with the increasing in tungsten doping. Moreover, near band edge emission gradually increased with increase in W content (up to about 0.5 wt%), and then abruptly decreased due to the concentration quenching effect.