The present work is focused on fabrication of reduced graphene oxide/iron­(II/III) oxide/polyaniline (RGO/Fe3O4/PANI) ternary composite by a hydrothermal method, its characterization, and application in the development of a high microwave absorbing shielding material. The RGO/Fe3O4/PANI composite showed dramatic enhancement of dielectric loss and magnetic loss compared to Fe3O4/PANI and RGO/Fe3O4 binary composites. This is ascribed to the embedment of more heterostructure phases. As a result, RGO/Fe3O4/PANI showed remarkably high SET (∼28 dB) through the absorption dominant mechanism. Our findings also showed maximum R L of Fe3O4/PANI, RGO/Fe3O4, and RGO/Fe3O4/PANI in the range of 2–8 GHz corresponding to −25 to −35, −40 to −46, and approximately −64 dB, respectively. This is in all probability due to the good impedance matching between permittivity/permeability and dielectric/magnetic losses.