This study presents findings on the AC impedance characteristics of rare earth-doped Co0.5Mn0.5RExFe2-xO4 ferrites (where RE = Er and Sm, and 0.0 ≤ x ≤ 0.1), synthesized utilizing the citrate auto-combustion process. Employing impedance spectroscopy at frequencies ranging from (100 − 1 MHz) and temperatures between 30◦C and 120◦C, we distinguished the impact of grains (Gs) and grain boundaries (GBs) in these compositions. The Jonscher power law was applied to characterize the AC conductivity results. The dielectric constant έ and dielectric loss ε” decline as the frequency rises and reach a stable state at higher frequencies, indicating the characteristic dielectric dispersion. This phenomenon manifests the Maxwell-Wagner polarization, as described by Koop’s hypothesis. The modified Debye formula provides a good match for the frequency-dependent dielectric permittivity fluctuation. The Cole-Cole plots revealed a single semicircle for the unaltered sample and lower Er3⁺ concentrations (up to x=0.02), but two semicircles appeared at higher Er3⁺ concentrations and in the Sm3⁺ doped samples. The G and GB resistances increased with higher concentrations of Er3⁺/ Sm3⁺ but showed a decrease at x=0.1 in Sm3⁺-doped samples. The data examination designates that the resistive and capacitive possessions are predominantly affected by G and GB processes. A relaxation phenomenon in the existing samples is shown by the frequency-dependent of the imaginary portion of impedance (Z"). Remarkably, the relaxation time (τz) showed linear temperature dependence. Additionally, studies of the electrical modulus (M’ and M”) highlighted nonDebye sort dielectric relaxation in all compositions, with peaks in the imaginary modulus indicating a shift in charge carrier mobility from long-range toward short-range. The investigation focused on the non-Debye relaxation, which was analyzed by determining the stretching exponential parameter (β). This factor was obtained by fitting the modified Kohlrausch-Williams-Watts (KWW) formula to the graph of the imaginary electric modulus. The substitution of Fe3+ by Er3+ and Sm3+ ions substantially enhanced the dielectric properties, particularly Co-Mn-Sm ferrite series, suggesting their potential use in high-frequency devices.