Nickel doped SnO2 thin films at different Ni doping concentrations were prepared using flash evaporation technique.The effect of Ni doping concentration on structural, optical and magnetic properties of thethin films was studied. X- ray diffraction studies revealed that all the Ni doped SnO2 thin films were in tetragonal structure. No traces of impurities were found even at higher Ni (15 at.%) doping level. Theoptical band gap of the filmsincreased withthe increase of Ni doping levelfrom 3 at.% to 15 at.%. All the Ni doped SnO2 thin films exhibited ferromagnetism at room temperature. The saturation magnetic moment (Ms) increased with increase of Ni doping level from 3 at.% to 7 at.% and then it decreased by further increase of Ni doping levels.