This study shows a facile approach for the preparation of CeO 2 nanoparticles decorated with porous nitrogen-doped graphene (NG) nanosheets for effective photocatalytic degradation of methylene blue (MB). NG nanosheets were first synthesized using a hydrothermal method and then nitrogen-doped graphene-cerium oxide (NG-CeO 2 ) was prepared through mixing of cerium nitrate with different concentrations of NG under ultrasonication followed by hydrothermal treatment. The synthesized nanocomposites were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE-SEM). The photocatalytic activity of the synthesized nanocomposites was analyzed against MB dye. Results showed that the nanocomposites of NG-CeO 2 have an average particle size of 20 nm. The as-prepared NG-CeO 2 nanocomposites exhibited outstanding photocatalytic activity for dye degradation under visible light irradiation, which could be attributed to synergistic effects between the NG nanosheets and CeO 2 . The quantum of photodegradation increases with the increase of the NG content in the nanocomposites.