The effects of the Ca 0.7Nd 0.2TiO 3 ceramic addition on the crystallization, densification, and dielectric properties of CaO–B 2O 3–SiO 2–(Al 2O 3) glass (C1: CaO–B 2O 3–SiO 2 glass and C1A03: CaO–B 2O 3–SiO 2–Al 2O 3 glass) for low-temperature co-fired ceramic (LTCC) applications are investigated. The cristobalite phase crystallized from C1 glass was inhibited by adding Al 2O 3. During sintering, Ca 0.7Nd 0.2TiO 3 ceramic reacted with CaO–B 2O 3–SiO 2–(Al 2O 3) glass to form the sphene (CaTiSiO 5) phase. The amount of sphene phase increases with increasing sintering temperature. By adding 50–60 wt% C1 or C1A03 glass, Ca 0.7Nd 0.2TiO 3 can be densified at 850–900 °C. The relative dielectric constants for Ca 0.7Nd 0.2TiO 3 added with C1 and C1A03 glasses were all 20–23. Ca 0.7Nd 0.2TiO 3 added with C1 glass exhibited a lower dielectric constant than C1A03 glass due to cristobalite phase formation. For Ca 0.7Nd 0.2TiO 3 ceramics added with 50 wt% glass, the variation in Q × f value presented the same trend as the sphene formation amount variation. The best Q × f value of 2380 GHz was achieved for Ca 0.7Nd 0.2TiO 3 ceramics added with 50 wt% C1A03 glass sintered at 900 °C due to the dense structure and greater amount of sphene. Ca 0.7Nd 0.2TiO 3 ceramics added with 50 wt% C1A03 glass sintered at 900 °C exhibited a dielectric constant of 22.8 and Q × f value of 2380 GHz, which are suitable for microwave LTCC applications.