The effects of ZnO and B2O3 addition on the sintering behavior, microstructure, and the microwave dielectric properties of 5Li2O-1Nb2O5-5TiO2 (LNT) ceramics have been investigated. With addition of low-level doping of ZnO and B2O3, the sintering temperature of the LNT ceramics can be lowered down to near 920°C due to the liquid phase effect. The Li2TiO3ss and the “M-phase” are the two main phases, whereas other phase could be observed when co-doping with ZnO and B2O3 in the ceramics. And the amount of the other phase increases with the ZnO content increasing. The addition of ZnO does not induce much degradation in the microwave dielectric properties but lowers the τf value to near zero. Typically, the good microwave dielectric properties of εr = 36.4, Q × f = 8835 GHz, τf = 4.4 ppm/°C could be obtained for the 1 wt% B2O3 and 4 wt% ZnO co-doped sample sintered at 920°C, which is promising for application of the multilayer microwave devices using Ag as internal electrode.