Radiation enhanced adhesion of metallic thin films to insulating substrates has received considerable recent interest. However, the effect of ionizing radiation on the adhesion of insulating thin films to insulating substrates has not been investigated. We report on tests to determine whether or not adhesion of ZnS films to an SiO2substrate is improved by irradiation with low energy electrons or high energy Cl6+ions. A positive adhesion increase upon irradiation amounting to a factor of five improvement over unirradiated samples, has been found.