Complexes of arsine ligands (R3As, R = Me, Et, Ph) and Lewis acids of group-13 elements of the form EX3 (E = B, X = Ph, C6F5; E = Al, X = Cl, Br, I; E = Ga, X = Cl) have been isolated and characterized by X-ray crystallography, infrared spectroscopy, 1H, 13C1H}, 11B1H}, and 27Al NMR spectroscopy. The compounds are compared with rare arsine–triel adducts.