Mundaú Lagoon is an estuarine lagoon situated west of Maceió, capital city of Alagoas state, in Brazil. Its total area is 24 km². The lake receives the Mundaú River, and is connected to the Atlantic Ocean and Manguaba Lagoon by a network of canals which cross the plain forming a lot of little islands. The lagoon contains to large mangrove and numerous types of fish, crabs, shrimps and shellfish. Mundaú Lagoon is the northernmost of several coastal lakes with the same features, including Manguaba, Roteiro and Jequiá lagoons.

Maceió, formerly sometimes Anglicised as Maceio, is the capital and the largest city of the coastal state of Alagoas, Brazil. The name "Maceió" is an Indigenous term for a spring. Most maceiós flow to the sea, but some get trapped and form lakes.