Açailândia (Portuguese pronunciation: [ˈasajlɐ̃dʒiɐ]) is a Brazilian municipality in the western part of Maranhão State, at an elevation of 787 feet (240 m).

Its population in 2020 was estimated to be 113,121, making it the eighth largest city in the state.

The city is an important center of agribusiness, the area having the largest cattle stock in Maranhão.

The production of pig iron is the municipality's biggest single economic activity.

Açailândia is part of the Carajas Development Corridor and the city houses many of the workers who produce charcoal in the area.