The effect of Li substitution on the structural and magnetic properties of LixCu0.12Mn0.88−2xFe2+xO4(x= 0.00, 0.10, 0.20, 0.30, 0.40, and 0.44) ferrite nanoparticles prepared by combustion technique has been investigated. Structural and surface morphology have been studied by X-ray diffractometer (XRD) and high-resolution optical microscope, respectively. The observed particle size of various LixCu0.12Mn0.88−2xFe2+xO4is found to be in the range of 9 nm to 30 nm. XRD result confirms single-phase spinel structure for each composition. The lattice constant increases with increasing Li content. The bulk density shows a decreasing trend with Li substitution. The real part of initial permeability (μi′) and the grain size (D) increase with increasing Li content. It has been observed that the higher theμi′is, the lower the resonance frequency in LixCu0.12Mn0.88−2xFe2+xO4ferrites is.