The dispersed, photocatalytic, and optical properties of TiO2 nanoparticles doped with sulfur and tin have been studied. The dependence of the TiO2 band gap on the content of dopants is determined. It is shown that the simultaneous doping of titanium dioxide with tin and sulfur increases the photocatalytic activity of the material compared to that for undoped material, and the band gap decreases to 2.98 eV, which is 0.13 eV less than in the case of doping with tin alone.