In the paper, the results of investigations in dielectric properties of composites (TGS)1−x/(BaTiO3)x with x = 0.10 and 0.20 have been presented. The composites were prepared by mixing TGS powders with BaTiO3 nanoparticles (3−5 μm and 400 nm in size, relatively). The sample surfaces were examined by electron microscopy, the temperature dependencies of permittivity of the subjects of investigation were studied. To control the effective spontaneous polarization of the samples, their pyroelectric effect was measured. In order to do it, the samples were previously polarized at room temperature. In heating, for composite samples, an increase ΔТс ≈ 3 deg.C in the Curie temperature was revealed for TGS contained in the composites, a rise in the permittivity of composites and a decrease in the tangent of their dielectric loss angle compared with pure TGS samples. The appearance of temperature hysteresis and blurring of the TGS phase transition taking place in the composites was detected.