New temperature-stable low-loss ceramic–glass composites based on Li2ATi3O8 (A=Mg, Zn) ceramics have been prepared by the conventional solid-state ceramic route. The effect of lithium magnesium zinc borosilicate (LMZBS) glass addition on the sinterability, phase purity, microstructure, and microwave dielectric properties of Li2MgTi3O8 (LMT) and Li2ZnTi3O8 (LZT) dielectric ceramics has been investigated for low-temperature co-fired ceramic applications. The LMT+3 wt% of LMZBS glass sintered at 925°C/4 h has ɛr=24.5, Qu×f=44,000 GHz, and τf=(+)0.2 ppm/°C. Addition of LZT ceramics with 3 wt% of LMZBS glass sintered at 900°C/4 h has ɛr=23.2, Qu×f=31,300 GHz, and τf=(−)15.6 ppm/°C. The LMT and LZT ceramic–glass composites do not react with the commonly used silver electrode material.