Lang's red colobus (Piliocolobus langi) is a species of red colobus monkey. Historically it had been treated as a subspecies of the Central African red colobus, (P. foai) but more recent taxonomies generally treat it as a separate species.

Lang's red colobus lives in lowland rainforest in the northeastern portion of the Democratic Republic of the Congo between the Lualaba River and the Aruwimi-Ituri River. It eats leaves, fruit, flowers, buds and possibly seeds. Males have a head and body length of about 50 cm (20 in) with a tail length of about 66.5 cm (26.2 in). Females have a head and body length about 48.5 cm (19.1 in) with a tail length of between 44 and 66.5 cm (17.3 and 26.2 in). Males weigh about 9 kg (20 lb) and females weigh about 7.7 kg (17 lb).