Low‐loss ceramics in the system (Mg1−xNix)2TiO4 (x=0.02–0.1) have been prepared using the conventional solid‐state ceramic route. The formation of (Mg1−xNix)2TiO4 (x=0.02–0.1) solid solutions was confirmed by the EDX analysis and the lattice parameters measured, which linearly varied from Mg2TiO4 (a=b=c=8.4410 Å) to (Mg0.9Ni0.1)2TiO4 (a=b=c=8.4335 Å). The X‐ray diffraction analysis also confirmed the coexistence of a cubic‐structured (Mg1−xNix)2TiO4 and an ilmenite‐structured second phase (Mg1−xNix)TiO3. By increasing x, not only could the Q×f of the (Mg1−xNix)2TiO4 solid solution be considerably increased from 150,000 GHz at x=0 to a maximum 238,000 GHz at x=0.05, the highest ɛr∼16.43 could also be obtained simultaneously. This was mainly due to the uniform grain morphology and the highest density of the specimen. A good combination of microwave dielectric properties (ɛr∼16.43, Q×f∼238,000 GHz at 9.8 GHz, and τf∼−55 ppm/°C) can be achieved for a specimen using (Mg0.95Ni0.05)2TiO4 sintered at 1400°C for 4 h.