Lithocarpus jacobsii is a tree in the beech family Fagaceae. It is named for the Dutch botanist Marius Jacobs. Trees in Lithocarpus are commonly known as the stone oaks and differ from Quercus primarily because they produce insect-pollinated flowers.
Lithocarpus jacobsii grows as a tree up to 36m (118feet) tall with a trunk diameter of up to 60cm (20inches). The brown bark is smooth or lenticellate. The coriaceous leaves are unusual and distinctive because of their cordate base that often seems to clasp the stem on a short petiole. The oblong leaves can be quite large, measuring up to 56cm (22inches) long and are glabrous and the same color on both the upper and lower sides (concolorous), with prominent secondary veins below and a looping marginal vein.
The infructescence can be quite long with numerous clusters of fruit scattered along the rachis. The fruits are generally in clusters of 3 (and up to 10). The cupules only cover the lower part of the nut and have squamose scales arranging loosely in cyclical series. The brown nuts are also glabrous and ovoid to roundish and measure up to 2.80NaN0 across.
Lithocarpus jacobsii is endemic to Borneo. Its habitat is mixed dipterocarp to lower montane forests up to 1300m (4,300feet) altitude.