Single phase of BaFe12-xNbxO19 ( x <= 0.1) hexaferrites ( HFs) were fabricated via citrate sol-gel route. The Ba hexaferrite formation has been confirmed by XRD and FE-SEM. The conductivity and dielectric properties of some Nb3+ ions-substituted BaFe12O19 hexaferrites ( Ba-HFs) were studied extensively via impedance spectroscopy. Some important parameters; dielectric constant, conductivity, dielectric loss, complex modulus and dissipation factors were analysed at temperatures up to 120 degrees C in 1.0 Hz to 3.0 MHz in frequency interval for various Nb substituents. Frequency dependent conductivity was found to be in accordance with the power laws with various exponents in all frequencies studied here. Such variation can be attributed to a characteristic conduction mechanism based on tunnelling processes. Furthermore, it is clear that the contribution of the dielectric response to the dielectric parameters between grains and grain boundaries can be interpreted in a certain frequency range.