The goal of this work is to study the influence of maleic anhydride-grafted poly(lactic acid) compatibilizer (PLAgMA) on morphology, thermal and barrier properties of poly(lactic acid) (PLA)/graphene oxide (GO) nanocomposites. Graphene oxide was synthesized from graphite flakes using modified Hummers method. The nanocomposites were prepared by the incorporation of graphene oxide into PLA via solution casting. The formation of nanolayers of graphene oxide was confirmed by Fourier transform infrared spectroscopic analysis, scanning electron microscopy and atomic force microscopy measurements. A maximum in elastic modulus G' measured at low frequencies was identified for the PLA containing 3 wt% GO and 3 wt% PLAgMA, which indicates a better dispersion of GO in the presence of compatibilizer and, therefore, yield better thermal and barrier properties of the nanocomposites.