Dysprosium substituted Magnesium ferrite weresuccessfully prepared by chemical combustion method. The as synthesized powder was presintered in air at 600⁰C for 1hr and finally sintered at 950⁰C for 1hr. From X-ray powder diffraction pattern of MgDy_0.03Fe_1.97O_4, confirmed formation of single phase cubic spinel structure. The value of crystallite size obtained from X-ray powder diffraction (311) peak , it is found to be 46.38nm.The frequency and temperature variation of dielectric parameters such as real dielectric constant (ε′), complex dielectric constant (ε") and dielectric loss tangent (tanδ) were determined using Hioki LCR - Q meter. The frequency variation of dielectric constant shows a normal dielectric behavior of spinel ferrites. The dielectric loss tangent with frequency shows similar behavior as dielectric constant. The dielectric constant and dielectric loss tangent increases with increase in temperature