The Western Guinean lowland forests are a tropical moist broadleaf forest ecoregion of West Africa. The ecoregion includes the lowland forests extending from the Atlantic Ocean a few hundred kilometers inland, and from western Côte d'Ivoire across Liberia, southeastern Guinea, most of Sierra Leone, and into southwest Guinea.
The Sassandra River of Côte d'Ivoire separates the Western Guinean forests from the Eastern Guinean forests which lie to the east. Inland and to the west, the Western Guinean forests transition to the Guinean forest-savanna mosaic, and to the Guinean montane forests at higher elevations.
The Western Guinean forests, together with the other tropical moist forests of West Africa, is included within Conservation International's Guinean Forests of West Africa biodiversity hotspot.