Lasjia whelanii, also known as Whelan's silky oak, Whelan's nut oak or Whelan's macadamia, is a species of large forest tree in the protea family that is endemic to north-eastern Queensland, Australia.
The tree was first described in 1889 by Queensland's colonial botanist Frederick Manson Bailey as a species of Helicia, which in 1901 he moved to Macadamia, but was transferred in 2008, in a paper in the American Journal of Botany by Peter Weston and Austin Mast, to the new genus Lasjia.
The dark green leaves grow up to long by wide, with four or five leaves in each whorl. The white flowers grow as inflorescences. The globular fruits are about in diameter, with the seeds strongly cyanogenetic (cyanide producing) and poisonous to humans. It produces a useful timber, suitable for construction work.
The species occurs in the Wet Tropics of Queensland, in well-developed lowland tropical rainforest, from near sea level to an altitude of .