The metal complexes of lanthanum(III) and cerium(III) with Schiff bases derived from the condensation of 2‐hydroxy‐1‐naphthaldehyde with α‐amino acids, viz. glycine, alanine, phenylalanine, valine, leucine and L‐glutamine, have been prepared and studied. The structures of these complexes are assigned on the basis of elemental analyses, molar conductance, IR and 1H NMR spectra and thermal analyses data. The results suggest that all of the Schiff bases behave as dianionic tridentate (ONO) ligands except the Schiff base derived from L‐glutamine which behaves as dianionic tetradentate (OONO) ligand. The apparent formation constants of the various complexes were determined spectrophotometrically and are discussed.