Nanocomposite zinc ferrites were synthesized using glycine-nitrates by sol–gel auto-combustion technique. The influence of calcination temperatures varying from 400 to 900°C on structural and magnetic properties of spinel ZnFe2O4 powders have been investigated. The characterization measurements including X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) were performed for as-synthesized zinc ferrite particles. In brief, the effect of calcination temperature on magnetic behavior, demonstrated that, the magnitude saturation magnetization (Ms) and remnant magnetization (Mr) were decreased with the increasing temperature for synthesized samples. In turn, the coercivity (Hc) and the shape of the hysteresis curve are affected significantly by calcination temperature. The coercivity (Hc) is closely related to the microstructure, particle/grain size, shape of the pores of the crystals, and many other complex factors. The calcined sample at 400°C has the best magnetic properties with the highest Ms of 16. 24 emug-1, and with Hc of 102.79Oe (at 10 kOe).