Highly transparent ZnO thin films were prepared using spray pyrolysis of a solution containing Zn(OAc)2 and SbC13 on glass substrates kept at 400ºC. Further, these films were doped with Sb by in situ process by dissolving SbCl3 in the spray solution. Crystallographic structural analysis was done using X-ray diffractometer and elemental analysis was done using Auger electron spectrometer. Morphological characterization was done by atomic force microscopy. The UV-Vis transmittance measurements indicated that the films were 90% transparent in the visible region. The value of band gap energy calculated from UV-Vis characterization showed that undoped and Sb doped films have slightly different band-gap energies. The electrical resistivity measurements showed a substantial change in the resistance of the ZnO thin films due to Sb doping.