In this paper, electromagnetic shielding properties of reduced graphene oxide (RGO) composites with cerium-doped lanthanum ferrite, La0.9Ce0.1FeO3 (LCFO), are studied. The synthesis procedure adopted is incipient wetness impregnation with SBA-15 as a template for LCFO and modified Hummer’s method for GO. The composites are synthesized by in-situ reduction of GO in the presence of LCFO, which acts as a magnetic filler in the weight ratios 1:0, 1:1, 2:1, 3:1 and 1:2 of LCFO and GO. X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FE-SEM) and nitrogen absorption/desorption isotherm are used to investigate the structural properties. Vector network analyzer (VNA) is used to ascertain the shielding and dielectric properties. The La0.9Ce0.1FeO3-reduced graphene oxide (LCFG31) composite shows appreciable electrical conductivity of 81.43 S/m and an effective BET surface area value of 23.93 m2g-1. It attenuates >99.99% of electromagnetic waves, and a shielding effectiveness (SE) value of 41.82 dB at a thickness of 2.36 mm in the Ku frequency band (12.4 - 18 GHz) has been achieved. The heterogeneous interfaces in the composite structure result in orientational and space charge polarization. The inclusion of magnetic ferrite as filler in composite incurs eddy current loss and magnetic losses. All these factors collectively make the composite material a good choice for electromagnetic shielding which can be further used for commercial applications.