Abstract: Reduced graphene oxide (rGO) aerogels are emerging as very attractive scaffolds for high-performance electromagnetic wave absorption materials (EWAMs) due to their intrinsic conductive networks and intricate interior microstructure, as well as good compatibility with other electromagnetic (EM) components. Herein, we realized the decoration of rGO aerogel with Mo₂C nanoparticles by sequential hydrothermal assembly, freeze-drying, and high-temperature pyrolysis. Results show that Mo₂C nanoparticle loading can be easily controlled by the ammonium molybdate to glucose molar ratio. The hydrophobicity and thermal insulation of the rGO aerogel are effectively improved upon the introduction of Mo₂C nanoparticles, and more importantly, these nanoparticles regulate the EM properties of the rGO aerogel to a large extent. Although more Mo₂C nanoparticles may decrease the overall attenuation ability of the rGO aerogel, they bring much better impedance matching. At a molar ratio of 1:1, a desirable balance between attenuation ability and impedance matching is observed. In this context, the Mo₂C/rGO aerogel displays strong reflection loss and broad response bandwidth, even with a small applied thickness (1.7 mm) and low filler loading (9.0wt%). The positive effects of Mo₂C nanoparticles on multifunctional properties may render Mo₂C/rGO aerogels promising candidates for high-performance EWAMs under harsh conditions.