The effects of ZnO glass addition on the microwave dielectric properties of Ni0.5Ti0.5NbO4 (NTN) ceramics prepared by solid-state reaction method have been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). The pure NTN ceramics have epsilon(r) of 60.6, Q x f value of 70,100 GHz, and tau(f) value of 76.6 ppm degrees C-1 sintered at 1140 degrees C for 6 h. The results indicate that the addition of ZnO can effectively benefit the densification and further improve the dielectric constant. Moreover, the lower sintering temperature of NTN ceramics from 1140 to 930 degrees C is obtained by the addition of ZnO glass. However, an excess of ZnO suppresses the grain growth and decreases the Q x f value of NTN ceramics. The NTN ceramics with 2 wt% ZnO sintered at 930 degrees C for 6 h possess promising microwave dielectric properties: epsilon(r) of 56.3, Q x f value of 67,000 GHz, and tau(f) value of 78.6 ppm degrees C-1, which shows that the materials are suitable for low-temperature co-fired ceramics applications. (C) 2014 Elsevier B.V. All rights reserved.