Density functional theory (DFT) calculations have carried out to investigate the nonlinear optical response of the B-40 fullerene by interaction with the alkali metals (Li, Na, K). The results reveal that the interacted fullerenes are energetically favorable. The B-40 electronic properties are strongly sensitive to the interaction with the alkali metals. Furthermore, the adsorption of the alkali metals over the B-40 hexagonal ring remarkably enhances the first hyperpolarizability up to 23111.72 a.u. Therefore, the B-40 fullerene interacted with the alkali metals could be introduced as a promising innovative nonlinear optical boron-based nanomaterial. (C) 2016 Elsevier B.V. All rights reserved.