The delamination buckling behavior of graphene Nano platelets (GNP) reinforced 3D fiber-metal laminates (3DFMLs) is investigated experimentally and numerically. In this study, the resin used to bond the metallic layers to the 3D fiberglass fabric (3DFGF) is reinforced with GNP, with the aim of improving the delamination resistance at the interface, thus enhancing the overall stability response of the 3DFMLs. For that, four different weight-percentages of GNP are used to establish the effect of GNP content on the stability (buckling) response of the 3DFMLs. In total, four groups of specimens with four different delamination lengths are used to investigate the effects of GM) on the buckling capacity of the 3DFMLs. In addition to the experimental investigation, a nonlinear finite element model is developed, using the commercial finite element code ABAQUS, to simulate the delamination buckling response of the 3DFMLs. The numerically obtained critical buckling capacities and failure modes are compared to the experimental results. Good agreements between the finite element (FE) and experimental results are obtained.