Barium strontium gadolinium bismuth niobate (Ba0.1Sr0.81Gd0.06Bi2Nb2O9, BSGBN) ceramics were prepared by using the conventional solid-state reaction method. The dielectric permittivity, modulus and impedance spectroscopy studies on BSGBN were investigated in the frequency range, 45 Hz-5 MHz and in the temperature range from room temperature (RT) to 570 degrees C. The dielectric anomaly with a broad peak was observed at 470 degrees C. Simultaneous substitution of Ba2+ and Gd3+ increases the transition temperature of SrBi2Nb2O9 (SBN) from 392 to 470 degrees C. XRD studies in BSGBN revealed an orthorhombic structure with lattice parameters a = 5.4959 angstrom, b/a = 1.000, c = 25.0954 angstrom. Impedance and modulus plots were used as tools to analyse the sample behaviour as a function of frequency. Cole-Cole plots showed a non-Debye relaxation. Also, dc and ac conductivity measurements were performed on BSGBN. The electric impedance which describes the dielectric relaxation behaviour is fitted to the Kohlrausch exponential function. Near the phase transition temperature, a stretched exponential parameter beta indicating the degree of distribution of the relaxation time has a small value.