The magnetization dynamics in ZnO:Ag/NiFe heterostructures has been investigated through magnetoimpedance measurements. By annealing the ZnO:Ag layer during the production process of the samples, structural and magnetic features of the whole heterostructure are modified, showing that the dynamical magnetic response of the heterostructure is strongly dependent on the annealing temperature. The magnetoimpedance results are discussed in terms of the different mechanisms governing the magnetization dynamics at distinct frequency ranges and in terms of the evolution of the ZnO:Ag layer with annealing. The presented results open new roads for technological application of semiconductor/ferromagnetic heterostructures.