Abstract Nanocomposites of xZnFe 2O 4–(1 − x)BiFeO 3, x = 0.1, 0.2, 0.3, 0.4 have been prepared by sol–gel technique. The samples have been calcined at various temperatures ranging from 500 to 800 °C and then the effect of annealing temperature on dielectric and magnetic properties is studied. Transmission electron microscopy revealed the formation of powders of nano order size and the crystal size was found to be around 30 nm. The magnetic behavior is found to be strongly dependent upon concentration of Zn ferrite phase and annealing temperature. Enhancement of dielectric constant is observed for the samples with high ferrite concentration and antiferromagnetic Néel temperature is also evident for the samples with maximum ferrite concentration.