Leganés is a city in the Community of Madrid, Spain. Considered part of the Madrid metropolitan area, it is located about 11 km southwest of the centre of Madrid. As of 2018, it has a population of 188,425, making it the region's fifth most populated municipality. It covers an area of 43.09 km² and it is located at 667 m over sea level.

Leganás houses a branch of the Universidad Carlos III. It is connected to Madrid via the Cercanías (train, line C5), and Metrosur, one of the lines of Metro. Leganés has 6 Metrosur stations.

On 3 April 2004 five of the suspects in the 11 March 2004 Madrid attacks blew themselves up in an apartment building as police moved in to arrest them. All five were killed, along with one GEO police officer.