Two low-firing Li 2 M 2 (MoO 4 ) 3 (M = Co, Ni) dielectrics were prepared, and their microwave dielectric properties were investigated. The XRD patterns indicated both samples crystallized in an orthorhombic structure with different space groups. The microstructures, lattice parameters, and Raman spectra of these ceramics were also systematically studied. The microwave dielectric properties were obtained with ε r ~ 9.1, Q × f ~ 34 000 GHz and τ f ~ −72 ppm/°C for Li 2 Co 2 (MoO 4 ) 3 at 840°C, ε r ~ 9.6, Q × f ~ 28 000 GHz and τ f ~ −71 ppm/°C for Li 2 Ni 2 (MoO 4 ) 3 at 660°C. With 0.05 mol% Zn substitution, excellent microwave dielectric properties (ε r ~ 10.9, Q × f ~ 56 000 GHz and τ f ~ −62 ppm/°C) can be obtained for Li 2 (Ni 0.95 Zn 0.05 ) 2 (MoO 4 ) 3 at 660°C, indicating a very promising dielectric for LTCC or ULTCC applications at high frequencies. K E Y W O R D S dielectric materials/properties, electroceramics, microwaves How to cite this article: Huang C-L, Liou J-N, Tsai M-H, Huang W-C. Microwave dielectric properties of Li 2 M 2 (MoO 4 ) 3 (M = Co, Ni) for LTCC applications. Int J Ceramic Eng Sci. 2020;2:130-139. https://doi.