In this study, the effect of graphene oxide (GO) and reduced graphene oxide (rGO) nanoparticles on the corrosion protection performance of nanocomposite coatings containing particle mass concentration ranging from 0.25% to 1% in epoxy matrix was investigated in detail. In addition, the effect of the distribution of GO and rGO nanoparticles in epoxy matrix on the corrosion performance and rheology of the coatings was studied by mixing the nanocomposites with the ball milling for 24 and 48 h. The surface morphology of coatings was analyzed by field-emission scanning microscope. It was observed that oxygen groups in the graphene structure, the effective distribution of nanoparticles in the matrix and the amount of nanoparticle doped affected the corrosion protection performance. The best corrosion protection performance among all nanocomposite coatings was 0.75 wt% rGO/epoxy nanocomposite, which was milled for 48 h. GO/epoxy nanocomposite coatings exhibit hydrophilic properties in all mass fractions and mixing times. However, adding 0.5 and 0.75 wt% of rGO and milling 48 h resulted in hydrophobic nanocomposites. rGO nanoparticles had the best dispersion performance at 0.75 wt% concentration in the epoxy. The nonlinear rheological measurements revealed that rGO/epoxy nanocomposites exhibit non-Newtonian shear thinning behavior at the studied mass concentrations and milling times as opposed to the nanocomposites containing GO particles.