<p>Microwave dielectric ceramics with high thermal conductivities prepared through energy saving sintering routes attract much attention to meet the requirements of multi-functionalization applications and low-energy-consumption fabrications. Herein, microwave cold sintering process (MW-CSP), as a highly efficient sintering route, is proposed to fabricate (1-x)TiO₂-xBN microwave dielectric ceramics with improved thermal conductivities. All the samples are well densified with relative densities in the range of 93 and 99%. The energy consumption during sintering is reduced by more than 96% using MW-CSP compared with traditional thermal sintering. The in-plane thermal conductivity is significantly higher than that of out of plane, due to the high orientation of BN platelets. A high thermal conductivity of 14.82 W/m·ּּK is obtained, which is 6.7 times higher than that of pure TiO₂. This work provides a route for the fabrication of microwave dielectric ceramics with controllable performances using a highly efficient sintering route.</p> Graphical abstract <p></p>