Dependence of microwave dielectric properties on the structural characteristics of (1−x)Ca 0.85 Nd 0.1 TiO 3 –xLnAlO 3 (Ln=Sm, Dy and Er) ceramics were investigated as a function of LnAlO 3 content (0.05≤x≤0.25). For the specimens with SmAlO 3 , a single phase with orthorhombic perovskite was obtained through the entire composition, however, Dy 2 Ti 2 O 7 and Er 2 Ti 2 O 7 were detected as a secondary phase along with the orthorhombic perovskite phase for the specimens with DyAlO 3 (x=0.25) and ErAlO 3 (0.10≤x≤0.25), respectively. With an increase of LnAlO 3 content, the dielectric constant decreased due to the smaller ionic polarizability of LnAlO 3 than Ca 0.85 Nd 0.1 TiO 3 . The temperature coefficient of the resonant frequency (TCF) decreased with LnAlO 3 content resulted from an increase of oxygen octahedral distortion.