The design and synthesis of highly efficient visible-light-driven photocatalysts through a facile, environmentally friendly, and economical method have become a key aim in the photocatalytic field. In this study, reduced graphene oxide grafted Ag3PO4 (RGO/Ag3PO4) composites with enhanced photocatalytic activity were prepared by the in situ deposition of Ag3PO4 nanoparticles on the surface of RGO sheets. The as-prepared RGO/Ag3PO4 composites were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV vis diffuse-reflectance absorption, Fourier transform infrared, and Raman spectrometry, and photoluminescence. The photocatalytic degradation of Rhodamine B (RhB) over RGO/Ag3PO4 composites was investigated and optimized, suggesting that the optimal amount of RGO in the composites was 3 wt %. The significantly enhanced photocatalytic activity and stability of RGO/Ag3PO4 composites could be attributed to the excellent electron-accepting and -transporting properties of RGO.