In this work, we used density functional theory with the Tkatchenko and Scheffler method to investigate the adsorption of diazinon, hinosan, chlorpyrifos, and parathion organophosphorus pesticides on the surface of B36N36 nanocage and its Fe doped derivatives. The assessments revealed that van der Waals interaction is a key factor in organophosphate adsorption on the surface of these nanocages as well as overlapping. The results of Fukui indices and atomic partial charges calculations indicated that these pesticides and nanocages act as nucleophile and electrophile, respectively, and the adsorption sites of all four organophosphates on these nanocages are thiophosphate groups, as well as the aromatic ring in diazinon, and the nitro group in parathion. In addition, the calculated adsorption energies yielded the best result for diazinon, and the best Fe doped B36N36 derivative for adsorbing organophosphates in aqueous solution is the one in which Fe atom is located in the boron position of the square ring of B36N36.