In this study, the dielectric response of Potassium (K+)-doped magnesium aluminates nanoparticles (Mg1−xKxAl2O4, x = 0.0, 0.25, 0.5, 0.75, 1.0) have been investigated as a function of frequency (20 Hz to 2 MHz) at room-temperature. Interestingly, the behavior of dielectric constant indicated the ionic or space charge polarization in the low-frequency range and it remains almost constant at high frequency. However, the value of conductivity increases at higher frequencies which is consistent with the previously reported results for the parent compound MgAl2O4. Moreover, the Cole–Cole plots represent various relaxation phenomena reflecting the existence of grain (boundaries) resistance effects. [ABSTRACT FROM AUTHOR]