This study prepared (1-x)BaTiO3–xCaTiO3(x=0–1) (denoted as BCT), (0.95-x)BaTiO3–xCaTiO3–0.05SrTiO3(x=0.00–0.95) (denoted as BS5CT), and (0.90–x)BaTiO3–xCaTiO3–0.10SrTiO3(x=0.00–0.90) (denoted as BS10CT) ceramics. Their preparation and structural and dielectric properties were characterized. The results show that the x-ray diffraction (XRD) peaks of the BCT, BS5CT, and BS10CT ceramics shift toward higher angles with increasing Ca. All samples were uniform and dense by 1400 °C sintering and the grain size decreased with the Ca addition. With the Sr and Ca cosubstitutions, the phase transition temperature (TC) decreased and the rhombohedral-orthorhombic and orthorhombic-tetragonal phase transition points disappeared. The dielectric peaks became increasingly broad and the relative dielectric constant of the BCT, BS5CT, and BS10CT samples decreased with increasing Ca. The replacement of Ba2+ ions by Sr2+ and Ca2+ ions reduced the lattice constant with increasing hydrostatic pressure and moved the Curie point downwards. The index of relaxation (γ) and the broadening parameter were estimated from a linear fit of the modified Curie–Weiss law.