Club Atlético Lanús (Spanish pronunciation: [ˈkluβ aˈtletiko laˈnus]) is an Argentine sports club based in Lanús, a city of the Buenos Aires Province. Founded in 1915, the club's main sports are football and basketball. In both sports, Lanús plays in Argentina's top divisions: Primera División (football) and Liga Nacional de Básquet (basketball). Domestic football major titles won by the club include two Primera División championships, the Copa Bicentenario and one Supercopa Argentina. At international level, Lanús has won one Copa CONMEBOL, and one Copa Sudamericana.

The so-called \"Southern Classic\" (\"Clásico del Sur\"), considered a modern classic in Argentine football, is contested against Banfield, and thanks to the good results of both in recent years it is also considered one of the most attractive clásicos of Primera División.

Apart from football, Lanús hosts many other sports such as athletics, gymnastics, martial arts, handball, field hockey, roller skating, swimming, tennis, volleyball, and weightlifting. Besides, the club has a futsal team in Colombia that was founded in 2011.