Graphene nanoplatelets (GNPs) employed as conductive fillers were added to an epoxy matrix, diglycidyletherof bisphenol-A (DGEBA), to enhance the electrical conductivity and electromagnetic shielding efficiency ofDGEBA. In addition, we investigated the influence of GNP fraction on the thermal properties, flexural strength, impactstrength, electrical conductivity, electromagnetic shielding efficiency, and morphology of DGEBA/GNP nanocomposites. The electrical properties indicated that the electrical conductivity of DGEBA/GNP nanocomposites consisting ofhigher than 7.5 wt% GNPs was significantly improved compared to that of pristine DGEBA. The electromagneticshielding efficiency of the nanocomposite showed a maximum value of 3.87 dB at 10 wt% GNPs, which is 287% higherthan that of pristine DGEBA. An analysis of the fracture surfaces of the nanocomposites showed a rough morphologywith numerous micro-cracks. In addition, the GNPs in the DGEBA matrix were stacked and formed a continuousconductive path at high GNP contents.