We have proposed the reactive templated grain growth (RTGG) method, in which highly textured ceramics are fabricated by the reaction between aligned template particles and supplementary ingredient materials. This process produces successive grain growth during heat treatment. A regular perovskite-type structured Bi_0.5(Na,K)_0.5TiO₃ (BNKT) bulk ceramic with a preferred <100> orientation was prepared using Bi₄Ti₃O₁₂ (BiT) platelets as a reactive template. The textured BNKT ceramics exhibited higher piezoelectric properties and a lower dielectric loss than randomly oriented ceramics with the same composition. The proposed method has been extended to bismuth layer-structured ferroelectrics and oxide thermoelectrics.