We describe and illustrate Magnolia nuevoleonensis A. Vázquez & Domínguez-Yescas, a new deciduous tree species that belongs to M. sect. Macrophylla Figlar & Nooteboom. It is morphologically similar to M. ashei Weath., but differs from the latter in being a larger tree, with smaller flowers, larger and broadly ovoid (vs cylindrical to ellipsoid) fruits, prominently beaked (vs shortly beaked) carpels, and firm and short (vs flexible and elongated) styles.