A redshift in the optical band gap of Manganese doped Zinc Oxide (Zn1−xMnxO) thin films has been obtained. The Zn1−xMnxO thin films obtained by sol gel spin coating method exhibit a 7.14% decrease in the optical band gap. The band gap narrows down from 3.22 eV to as low as 2.99 eV as the concentration of the dopant is increased from x = 0 to x = 0.6. The photoluminescence spectra also show a redshift of 106 meV in the ultraviolet emission peak i.e. NBE emission as the concentration of Manganese is increased in the thin films. The polycrystalline Zinc Oxide thin films with wurtzite hexagonal structure have been probed into with the help of X-ray diffraction spectroscopy, optical transmission spectroscopy and Fourier transforms infrared spectroscopy. Scanning electron microscopy revealed the granular surface of the Mn doped ZnO thin films.