C-Alkylation and O-alkylation of ethyl acetoacetate by a series of alkylating agents is investigated, in the gas phase as well as in the solvent, within a local viewpoint of the hard and soft acids and bases (HSAB) principle at the Hartree-Fock level using a 3-21+G* basis set. The Gazquez and Mendez formula for calculating the interaction energy is used to reveal the influence of the alkylating agent softness on the two possible orientations in the ethyl acetoacetate alkylation. O-Alkylation was found to be favored by a hard alkylating agent, whereas C-alkylation becomes less and less disfavored upon increasing softness.