Abstract: A glass frit containing Li₂O–MgO–ZnO–B₂O₃–SiO₂ component was used to explore the low-temperature sintering behaviors and microwave dielectric characteristics of tri-rutile MgTa₂O₆ ceramics in this study. The good low-firing effects are presented due to the high matching relevance between Li₂O–MgO–ZnO–B₂O₃–SiO₂ glass and MgTa₂O₆ ceramics. The pure tri-rutile MgTa₂O₆ structure remains unchanged, and high sintering compactness can also be achieved at 1150°C. We found that the Li₂O–MgO–ZnO–B₂O₃–SiO₂ glass not only greatly improves the low-temperature sintering characteristics of MgTa₂O₆ ceramics but also maintains a high (quality factor (Q) × resonance frequency (f)) value while still improving the temperature stability. Typically, great microwave dielectric characteristics when added with 2wt% Li₂O–MgO–ZnO–B₂O₃–SiO₂ glass can be achieved at 1150°C: dielectric constant, ε_r = 26.1; Q × f = 34267 GHz; temperature coefficient of resonance frequency, τ_f = −8.7 × 10⁻⁶ /°C.