"Hakea pachyphylla" was first formally described in 1827 by Curt Sprengel from an unpublished description by Franz Sieber in "Systema Vegetabilium".The specific epithet ("pachyphylla") is derived from the Ancient Greek words "pachys" (παχύς) meaning "thick" and "phyllon" (φύλλον) meaning "leaf" referring to the thickness of the leaves.