Abstract: In this paper, we present the calculation results of the electronic structure and optical spectrum and an experimental study of the optical properties of Heusler alloys Mn2 –xFe1 +xAl (x = –0.5, 0, 0.5, 1). An anomalous for metallic systems behavior of the optical conductivity of alloys in the IR region of the spectrum was found: the absence of Drude growth and a high level of interband absorption. This behavior is shown to be determined by the features of the electronic structure: the Fermi level is located in the region of high density of states that is formed by the d states of Mn and Fe. © 2023, Pleiades Publishing, Ltd.