The Lisbon Metropolitan Area (Portuguese: Área Metropolitana de Lisboa; abbreviated as AML) is a metropolitan area in Portugal centered on Lisbon, the capital and largest city of the country. The metropolitan area, covering 17 cities in 18 municipalities, is the largest urban area in the country and the 11th largest in the European Union, with a population in 2024 of 3,005,119 in an area of 3,015.24 km².

The Lisbon Metropolitan Area has the largest GDP (€98.5 billion) of any metropolitan area in Portugal. The region is home to the largest tech hub in the country and a majority of Portugal's major multinational corporations by revenue are based there.

Portugal has been through a period of administrative changes since the 1974 revolution. More recently, new standards of territorial administration have been implemented to match European Union criteria.

After some years of indefinitions, municipalities are now associated in metropolitan areas or intermunicipal communities. These new regional divisions are colliding with the traditional Portuguese regional structures: Distritos (Districts). Districts were implemented in the 19th century by Mouzinho da Silveira after the Liberal Revolution of 1820, to replace clerical dioceses (which held the intermediate authority between the absolute monarchy and the municipalities), and still are the official regional authorities in Portugal, thus leaving the new metropolitan authorities with no authority at all. For instance, the District of Lisbon and the District of Setubal collide and interfere with the Lisbon metropolitan area authority. Each District is ruled by a governador civil (civil governor). These governors are empowered by the Prime Minister of Portugal and have most of the administrative power over the municipalities comprised, leaving the metropolitan areas with a passive status and communitarian tasks.

As an administrative entity, the Lisbon metropolitan area was only created in 1991 in order to meet the needs of urban territories with a large population density surrounding the Portuguese capital.

To definitely end with these anomalies, a national Referendum was held on November 8, 1998, in order to approve a new regionalization, which was rejected by over 60% of the voting population on account of disagreements over the loss of sovereignty of some districts to others (e.g. by the time of the referendum it was not known where the seat of government of the new "Estremadura & Ribatejo" region would be, which was a fusion of the District of Leiria with the District of Santarém, Leiria and Santarém being cities of the same size and importance).

The Regionalization experiment in Portugal was only successful among insular regions like in 1976, when the districts of Angra do Heroísmo, Horta and Ponta Delgada were substituted by the Autonomous Region of Açores with the seat of government being in Ponta Delgada, while the district of Funchal was replaced by the Autonomous Region of Madeira with a seat of government in Funchal.

The Lisbon metropolitan area, centered in the Portuguese capital city of Lisbon, is the largest population concentration in Portugal. The population in 2011 was 2,821,876, of whom 547,733 (19.4%) live in the city of Lisbon. About 26.7% of the total population of Portugal lives in the Lisbon metropolitan area. The area of the Lisbon metropolitan area is 3,015.24 km², which is 3.3% of the total area of Portugal.