Banksia grossa is a species of shrub in the family Proteaceae and is endemic to Southwest Australia. It is one of fourteen species of banksia of the series Abietinae, all of which bear predominantly cylindrical or oval inflorescences. Collected in 1965, it was first formally described in 1981 by Alex George. Its thick leaves and large seeds distinguish it from other members of the Abietinae, and are the basis of its species name.