Zinc doped Nickel ferrites with chemical formula  (x = 0.2, 0.4, 0.6, and 0.8) were synthesized using both Sol-gel auto-combustion and Hydrothermal methods. The synthesized powders were characterized for their physical and magnetic properties. The crystal structure and lattice parameter of these compounds were investigated by X-ray diffraction (XRD) and morphology has been confirmed by Scanning Electron Microscopy (SEM). The magnetic properties of after-calcined nanoparticles were measured at room temperature using a vibrating sample magnetometer (VSM). X-ray diffraction of these samples shows the presence of a single-phase cubic spinel ferrite structure. The VSM analysis indicates that the Zn content has a significant influence on the magnetic properties such as Saturation Magnetization (Ms), Coercivity (Hc), and Remanence (Mr). The doping concentration of Zn increase with an increase of x which causes a significant increase in the Ms from x=0.2 to 0.4 then decrease from x=0.6 to 0.8. A critical Rietveld analysis of XRD reveals the presence of a very small amount of NiO phase along with the ferrite phase. The Rietveld analysis also confirms the crystallite size and lattice parameter.