Engelhardia mendalomensis is a tree in the family Juglandaceae. It is named for the Mendalom Forest Reserve in Borneo.
Engelhardia mendalomensis grows up to tall, with a trunk diameter of up to . It has buttresses up to high and extending out to . The bark is grey to brown. The leaves are falcate or lanceolate or ovate and measure up to long.
Engelhardia mendalomensis is native to Borneo (Sabah) and Papua New Guinea. Its habitat is mixed dipterocarp forests, to elevations of .