In this study we investigate optical, structural and electrochromic properties of sol-gel dip coated Nb2O5, WO3 doped and ZrO2 doped Nb2O5 thin films. The Nb2O5 sol was mixed with various percentages of WO3 and ZrO2 sols. The films were heat treated at 550degreesC for crystallization. Optical, structural and electrochromic properties of the films were investigated by using spectrophotometer, X-ray diffractometer, scanning electron microscope and cyclic voltammeter. Doping did not make any important change in the transmission spectra, but it made the surface of the Nb2O5 films smoother with respect to the undoped films. Nb2O5 films show good electrochemical reversibility. Total charge density of the Nb2O5 thin films was improved by doping.