The changes of ZnFe2O4 caused by mechanical activation as well as the structural evolution of non-activated and mechanically activated zinc ferrite occurring during heating, have been investigated by in situ Mossbauer spectroscopy. Attention is directed to mechanically induced changes in magnetic properties of zinc ferrite, the variation of nuclear quadrupolar interactions, the thermally induced changes of the Mossbauer shift, and also to the structural response of mechanically activated zinc ferrite to changes in temperature.