In a recent field survey at Mt. Tingtingan, Badong, Tago, Surigao del Sur, an interesting Begonia with a robust habit was found. With the cane-like, erect and ascending or spreading suffrutescent stem, 2-tepaled staminate flowers and 5-tepaled pistillate flowers, this species belongs to section Petermannia. It's worth noting that the staminate and pistillate flowers of this species exhibit different tepal colors. This new Begonia resembles its Surigao ally B. benitotanii in having erect and glabrous stems, leaf adaxial surface with sparsely white spots between veins, obliquely cordate base, acuminate apex and serrated margin, but the new species named Begonia matahom is distinct in having larger stems that are woody and thick, ovate to triangular leaf shape, larger lamina, longer petioles, longer bracts, glabrous staminate tepals, yellowish-green pistillate flowers, stigmas in a curled spirally extended band with prominent cilia to conspicuously feathery, and smaller green ovary with glabrous and thick, unequal wings.