To probe the kinetic performance of microsolvated α-nucleophile, the G2(+)M calculations were carried out for the gas-phase SN2 reactions of monohydrated and dihydrated α-oxy-nucleophiles XO−(H2O)n = 1,2 (X = HO, CH3O, F, Cl, Br), and α-sulfur-nucleophile, HSS−(H2O)n = 1,2, toward CH3Cl. We compared the reactivities of hydrated α-nucleophiles to those of hydrated normal nucleophiles.