Silver nanoparticles (AgNPs) decorated polyethylmethacrylate (PEMA)/Graphene oxide (GO) nanocomposites were prepared through in situ polymerization ethylmethacrylate (EMA) in presence of GO and AgNPs. PEMA/GO/Ag nanocomposites were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR), X‐ray diffraction analysis (XRD), and UV‐visible spectroscopy. The thermal stability of PEMA was considerably enhanced due to incorporation of GO and AgNPs and around 32% residue was obtained for PEMA/GO/Ag. This was due to the compatibility of the AgNPs with PEMA and surface functional group of GO. The oxygen barrier property of the PEMA/GO was become double due to incorporation of AgNPs, which was due to the uniform dispersion of AgNPs. The prepared PEMA/GO/Ag composites had shown high resistance to acid and alkali. The antimicrobial properties of composites were measured by Kirby‐Bauer method and the positive antimicrobial properties along with other enhanced properties enable the material suitable for antimicrobial packaging. POLYM. COMPOS., 40:E1199–E1207, 2019. © 2018 Society of Plastics Engineers