Rhododendron crassifolium is a species of tropical rhododendron, a perennial flowering plant belonging to the family Ericaceae. It is placed in section Schistanthe.
Rhododendron crassifolium is a tropical rhododendron native to mountainside forests of Borneo at . It is a medium size evergreen shrub about tall. Leaves are dark green, broad, ribbed and elliptic. The bell-shaped flowers are red-orange. The flowering period extends from June through August.
, Plants of the World Online accepted two species:
The species is native to the island of Borneo.
This species is typical of the shaded mountain forests. It prefers acidic, well-drained, organic soil in partial sun to partial shade.