Sintered composites of WC–WB–W₂B were prepared from B₄C–W–WC powders using a reactive energization hot-pressing technique that initiated a solid state reaction between B₄C and W. Below a WC mole fraction of 0.769 in the starting powder, WB and WC were formed according to the reaction B₄C+5W+xWC=WB+(1+x)WC, while WB, W₂B, and WC were produced above a mole fraction of 0.854. Densely sintered bodies were not obtained for pure WC. Composites of WC–WB–W₂B obtained at WC mole fractions between 0.854 and 0.956 were fully consolidated, having high Young’s modulus and Vickers hardness values, and a fracture toughness which were comparable to those of WC.