Pentachlaena orientalis is a tree in the family Sarcolaenaceae. It is endemic to Madagascar.
Pentachlaena orientalis grows as a tree up to tall with a trunk diameter of up to . Its leaves are elliptic and measure up to long.
Pentachlaena orientalis is known from the eastern regions of Alaotra-Mangoro, Analanjirofo and Atsinanana. Its habitat is humid forest from sea level to about altitude. Some subpopulations of the species occur in protected areas.