The study successfully synthesized Mg-doped Cu-Zn ferrite nanoparticles using a green and eco-friendly method, using green tea extract as a reducing and capping agent. The structural and magnetic properties of the nanoparticles were thoroughly examined using various analytical techniques. X-ray diffraction (XRD) confirmed the formation of a single-phase cubic spinel structure, with an average size of 18 nm. Fourier-transform infrared spectroscopy (FTIR) identified characteristic peaks at 400 cm-1 and 600 cm-1, which correspond to the stretching vibrations of metal-oxygen (M-O) bonds. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) showed a consistent spherical shape with an average size of 25 nm. The magnetic properties were significantly influenced by Mg doping, with saturation magnetization (Ms) increasing from 42.5 emu/g for undoped samples to 54.2 emu/g for Mg-doped samples. The coercivity (Hc) values showed a slight decrease, indicating enhanced magnetic stability. The study highlights the wide range of technological domains where these nanoparticles can be applied, taking advantage of their magnetic properties and environmental friendly synthesis.