Clermontia montis-loa is a shrub or tree with heights ranging from 2 to 5 meters and can be terrestrial or epiphytic. It features light gray or light brown stems that are repeatedly branched and spread out, with a solid pith and white, viscous latex. The leaves are simple and alternate, with oblanceolate or oblong blades 8–19 cm long and 2.2–4.5 cm wide, featuring dark green upper surfaces and pale green lower surfaces that may be suffused with purple. The inflorescences are typically 2 to 3-flowered and can be glabrous or pubescent. These flowers are bisexual, epigynous, zygomorphic (bilaterally symmetric), resupinate, and protandrous, with a hypanthium 1–1.6 cm long. The perianth is bilabiate, colored green or dark purple on the outside and dark purple within, with lobes that spread outward. The stamens are syngenesious, with dark purple anthers that open introrsely. The ovary is inferior, consisting of two carpels and two locules, with a large axile placentation. The style is slender and cylindrical, with a two-lobed stigma that becomes receptive after pollen release. The fruit is a subglobose or ellipsoid orange berry, 2.5–3 cm long and 1.5–3 cm in diameter, containing numerous tiny, dark brown or black seeds. These seeds have a minutely foveate-reticulate surface and include a straight, short to spatulate dicotyledonous embryo embedded in oily endosperm. It is found in montane rain forests at 1070-1700 meters.