The correlation of heating rates, crystal structures, and microwave dielectric properties of Li 2 ZnTi 3 O 8 ceramics was thoroughly investigated. Ionic polarizability, atomic packing fractions, bond strengths, and octahedral distortion of Li 2 ZnTi 3 O 8 ceramics were calculated on the basis of structure refinement data. The ''black core'' phenomenon resulting from reduction of Ti 4+ ions was observed for Li 2 ZnTi 3 O 8 ceramic sintered at 1°/min; reduction of Ti 4+ ions could be limited by heating more rapidly. For heating rates from 1 to 7°/min, the dielectric constants (e r ) of Li 2 ZnTi 3 O 8 ceramics were mainly determined by ionic polarizability. The temperature coefficient of the resonant frequency (s f ) of Li 2 ZnTi 3 O 8 ceramics was determined by bond strengths. Li 2 ZnTi 3 O 8 ceramic sintered at 1°/min had the lowest quality factor (Q 9 f); this was related to the high dielectric loss as a result of oxygen vacancies formed by reduction of Ti 4+ ions. Q 9 f values of Li 2 ZnTi 3 O 8 ceramics also decreased with increasing heating rate from 3 to 7°/min, owing to reduced packing fractions and average grain sizes. Li 2 ZnTi 3 O 8 ceramic sintered at 3°/min had the optimum microwave dielectric properties of e r = 26.6, Q 9 f = 83,563 GHz, and s f = À12.4 ppm/°C.