Abstract For ultrathin multilayer Co/Zr films the dispersion of optical and magneto-optical effects and the orientation dependence of the FMR fields have been measured. The magnitude of the equatorial Kerr effect in quasi-amorphous multilayer films in the visible light range is found to be almost independent of frequency, and its dependence on the thickness of the Zr layer does not correlate with variations in the magnetization. The components of the dielectric permeability tensor have been derived from optical and magneto-optical data. The frequency dependence of the absorption parts of the tensor components is interpreted on the basis of data on the electronic structure of pure Co and Zr. The FMR spectra exhibit auxiliary modes whose dependence on the field orientation is different from that of the main mode. The results are related to the effects of the exchange interaction of the Co layers in the multilayer structure.