The São Paulo Metro, commonly called the Metrô, is a rapid transit system that forms part of the urban railways that serves the city of São Paulo, alongside the São Paulo Metropolitan Trains Company (CPTM), both forming the largest metropolitan rail transport network of Latin America. The six lines in the metro system operate on 104.4 kilometres (64.9 mi) of route, serving 89 stations. The metro system carries about 4,300,000 passengers a day.

Rapid transit or mass rapid transit (MRT), also known as metro, is a type of high-capacity public transport that is generally built in urban areas. A rapid transit system that primarily or traditionally runs below the surface may be called a subway, tube, or underground. Unlike buses or trams, rapid transit systems are railways, usually electric, that operate on an exclusive right-of-way, which cannot be accessed by pedestrians or other vehicles. They are often grade-separated in tunnels or on elevated railways.