Belize River is a 180-mile (290 km) river in Belize that drains more than one-quarter of the country as it winds along the northern edge of the Maya Mountains across the center of the country to the sea near Belize City. Also known as the Old River, the Belize River is navigable up to the Guatemalan border and served as the main artery of commerce and communication between the interior and the coast until well into the twentieth century.

The create begins where the Mopan River and Macal River join in Guatemala. It flows through the Belize river valley which is largely comprised of tropical rain forest. The river has long been associated with forestry, particularly of mahogany, which still occurs.