The Sm 2 Si 2 O 7 ceramics were synthesized by solid-state ceramic route. The calcination and sintering temperature of Sm 2 Si 2 O 7 were optimized for the best properties. The crystal structure and microstructure of the ceramic were studied by X-ray diffraction and scanning electron microscopic methods. The low frequency dielectric properties were studied at 1 MHz. The dielectric properties of the ceramic were measured in the microwave frequency range by the cavity perturbation method. Sm 2 Si 2 O 7 has e r 5 12.5, tan d 5 8 Â 10 À4 , and t e 5 163 ppm/1C at 1 MHz and a relative permittivity of 10 and tan d of 6 Â 10 À3 in the microwave frequency range. The effect of addition of various low loss glasses such as 50ZnO-50B 2 O 3 (ZB), 2 (LBS) and 20Li 2 O-20MgO-20ZnO-20B 2 O 3 -20SiO 2 (LMZBS) on the microwave dielectric properties of Sm 2 Si 2 O 7 was also investigated. It was found that the addition of 15 wt% LBS glass reduced the sintering temperature from 13751C to 9751C with e r 5 9.89 and tan d 5 0.024. Fifteen weight percent LMZBS glass ceramic decreased the sintering temperature to 9501C with e r 5 9.09 and tan d 5 0.009. The results show that Sm 2 Si 2 O 7 mixed with suitable amounts of selected glasses is a promising material for microwave substrate applications.