The densification of B₄C by spark plasma sintering (SPS) with metal disilicides (MeSi₂) is explored. It is identified that MeSi₂ acts as a reactive sintering additive, forming in-situ SiC, the corresponding metal diboride (MeB₂), and Si, and that this latter promotes densification by transient liquid phase sintering with greater formation of SiC. The densifiability is studied as a function of the increasing proportion of MeSi₂ aids, demonstrating that a broad spectrum of full-dense B₄C–MeB₂–SiC composites can be obtained at increasingly lower SPS temperatures. Finally, it is shown that these B₄C–MeB₂–SiC composites have fine-grained microstructures and that they are superhard and tougher than monolithic B₄C ceramics, which together with their easier fabricability makes them very appealing for structural applications.