The doping of titanium dioxide (TiO2) with various metal or nonmetal elements has been considered as an effective strategy to extend the photoactive wavelength region to visible light. In this paper (nitrogen [N] and sulfur [S])-codoped anatase TiO2 nanoparticles were prepared via a sol-gel route, followed by a heat treatment at elevated temperatures. The as-prepared samples were extensively characterized by X-ray diffraction, UV-Vis absorption spectroscopy, and X-ray photoelectron spectroscopy. The N, S-codoped TiO2 nanoparticles showed a strong visible light absorption and exhibited an enhanced photocatalytic activity for the degradation of methylene blue as compared with the pure, N- or S-doped TiO2 under either UV light or solar light irradiation.