The present study explores, the pure and silver (Ag) doped WO3 nanoparticles synthesized by microwave irradiation method. Powder X-ray diffraction results reveal that the WO3 doped with Ag concentration from 0 to 10 wt% crystallizes in monoclinic structure. TEM analysis shows both pristine and silver doped WO3 nanoparticles. They are having spherical morphology with an average size from 30 to 40 nm. Scanning electron microscopy studies depicts that both the pristine and Ag doped WO3 form in spherical shaped morphology with an average diameter of 40–30 nm, which is in proper agreement with the average crystallite sizes calculated by Scherrer’s formula. A considerable red shift in the absorbing band edge and a decrease in the band gap energy from 3.00 to 2.85 eV for Ag doped samples were observed by using UV–DRS spectra analysis. The defects in crystal and oxygen deficiencies were analyzed by photoluminescence spectra analysis. © 2016 Elsevier B.V., All rights reserved.