Graphene oxide–CdS–Pt (GO–CdS–Pt) nanocomposites with different amounts of Pt nanoparticles were successfully synthesized via the formic acid reduction process followed by a two-phase mixing method. The morphology, crystal phase and optical properties of obtained composites were well characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-vis spectroscopy, Fourier transform IR spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS), respectively. The photocatalytic activity of GO–CdS–Pt composites for hydrogen generation was investigated. The results show that the GO–CdS–Pt composite containing 0.5 at% of Pt exhibits the highest hydrogen evolution rate of 123 mL h 1 g 1 with strong photostability, which is about 2.5 times higher than that of GO–CdS and 10.3 times higher than that of CdS. The increased photocatalytic hydrogen generation efficiency is attributed to the effective charge separation and decreased anti-recombination with the addition of GO and Pt, as well as the low overpotential of Pt for water splitting. Our findings pave a way to design multi-component graphene-based composites for highly efficient H2 generation and other applications.