Emilio Méndez Pérez (born 22 May 1949) is a Spanish physicist. His research has focused on the study of the optical and electronic properties of semiconductor nanomaterials. Particularly notable are his discoveries on the effects of an electric field on the electronic properties of quantum wells and superlattices, especially the experimental demonstration of the so-called " Stark effect " and the so-called " Wannier–Stark ladder ".