Monrovia's economy is centered on its harbor, home to the country's major commercial port, which has accommodated ocean-going vessels since improvements made in the 1940s with U.S. assistance. It is a free port, and vessels from countries around the world can obtain Liberian registration, giving the port one of the world's largest tanker fleets with more than 1,600 vessels. The main Liberian exports handled through the port are the country's two major natural resources, latex from rubber plantations and iron ore. Monrovia also has storage and ship repair facilities. Items manufactured in or near the city include food products, cement, bricks, tiles, furniture, and pharmaceuticals.

Following the civil war of the 1990s, Liberia, a country that was once prosperous by African standards, is one of the poorest countries on the continent, its economy decimated by displacement of its population and destruction of its infrastructure. Utility operation in Monrovia broke down in 1990, after which the city had no central power supply, and residents resorted to personal power generators. Now heavily dependent on foreign aid, Liberia faces the challenges of repatriating refugees who fled to neighboring countries, rebuilding its infrastructure, and restoring its public institutions.