The spinel ferrites with the compositional formula Ni0.8Zn0.2Fe2−xDyxO4 (x = 0, 0.004, 0.008, 0.012, 0.016) have been prepared using the sol–gel method. The X‐ray diffraction measurements confirm the cubic spinel structure of the sample with a space group of Fd‐3m. Morphological analysis of scanning electron microscope images reveals that the particles are spherical in shape. Energy dispersive X‐ray spectroscopy (EDX) confirms the elemental composition. Thermogravimetric analysis (TGA)/differential scanning calorimetry (DSC) analysis of synthesized dysprosium (Dy) doped Ni–Zn ferrites are carried out from 25 to 700 °C. Fourier‐transform infrared (FTIR) spectroscopy studies reveal the stretching and bending vibrations of the various bonds presented in the compounds. The UV–vis absorption spectrum indicates the energy gap values which small decrease with the Dy concentration increase. Raman spectroscopy reveals the crystal distortion and phases of the samples. The room temperature magnetic measurements (M–H loops) are carried out to study the effect of Dy doping on magnetic properties.