Epoxy resins are often used for the anti-wear purpose but their wear resistance is quite low and it is thus necessary to enhance their wear resistance. In this paper, the tribological performance of graphene oxide (GO)/epoxy nanocomposites is investigated for the first time at a very low GO weight fraction of 0.05 -0.5%. The friction and wear tests conducted on the GO/epoxy composites against smooth steel show that the wear resistance is significantly enhanced by the addition of GO to epoxy and the specific wear rate is reduced by 90.0-94.1% relative to the neat epoxy when the GO content is equal to 0.5 wt %. Comparisons with other nanofillers including SiO2, TiO2, Al2O3, Si3N4 and carbon nanotubes indicate that GO shows an obvious superiority in enhancing the wear resistance of epoxy resins at very low contents. The superiority of the GO nanosheets is related to their high specific surface area, good GO-epoxy adhesion arising from their wrinkled rough surface, oxygenous functional groups, twodimensional planar geometry and the enhanced glass transition temperature due to the introduction of GO. Finally, the friction and wear mechanisms were tentatively proposed for the GO/epoxy composites. (C) 2012 Elsevier Ltd. All rights reserved.