The influence of order–disorder structural transition on the magnetic, magneto-optical, and optical properties of nearly equiatomic FeAl alloy films was investigated. The disordered state in FeAl alloy films was obtained by means of vapor quenching deposition onto glass substrates cooled by liquid nitrogen. The experimental study of the magneto-optical and optical properties of ordered and disordered FeAl alloy films was carried out in the 0.5–5.0 eV energy range at room temperature. The influence of the order–disorder structural transition on magnetic, magneto-optical, optical properties is discussed by using the results of first-principle calculations of the electronic structure and by the structural defect approach. ©1997 American Institute of Physics.