Vanadium carbide (VC) nanocapsules with carbon shells have been synthesized via an arc discharge process. The nanocapsules are spherical in shape with a diameter distribution of 10–40 nm. Reflection losses exceeding −20 dB can be realized in any interval within the 6.6–18 GHz range by choosing an appropriate thickness of the absorbent layer between 1.4 and 3.5 mm. An optimal absorption value of VC/C nanocapsules with a thickness of 2.2 mm is −45.94 dB at 10.8 GHz. The electromagnetic-wave absorption properties of the nanocomposite are illustrated in detail by means of an absorption-tube-map. The VC nanocapsules are attractive candidates for electromagnetic-wave absorption.