Thin films of NiOAg were grown onto glass substrates by radio frequency (RF) sputtering technique at 13.56 MHz RF with variation in oxygen pressure. The research was conducted on preparation and characterization of NiOAg thin films, applicated as a photocatalyst for the degradation of methylene blue. X-ray diffraction analysis showed stronger intensity (111) and (200) planes at peak 2θ of 37.66° and 43.23°. Energy dispersive x-ray analysis showed the following composition: Ni = 40.45%, Ag = 13.01%, and O = 46.53%. Based on UV–vis, it was found that the bandgap energy was 2.8, 3.1, and 3.2 eV for oxygen pressures of 0.05, 0.1, and 0.15 × 10−2 mbar, respectively. From the experiment on the degradation of methylene blue, which was taken from textile factory dye waste in Yogyakarta/Indonesia, the best value of degradation was obtained as 91.96%. [ABSTRACT FROM AUTHOR]