The Metropolitan Transport Authority (Catalan: Autoritat del Transport Metropolità, ATM) is a public consortium intended to coordinate the operation and project the expansion of the public transport system in the Barcelona metropolitan area. It is made up of the Government of Catalonia and local administrations. It has been known as ATM Àrea de Barcelona since 2003 to differentiate it from the other existing Catalan public transport authorities in the Girona, Camp de Tarragona and Lleida areas, which are also identified as ATM. As of January 2015, the ATM-managed public transport system comprises 50 different operating companies and serves 346 municipalities, accounting for a population of over 5.7 million.

Created in 1997, the ATM has since developed an Integrated Fare System (Catalan: Sistema Tarifari Integrat, STI) based on concentric fare zones. There currently exist about 80 different types of multiple-time tickets or unlimited passes for use on the STI, all of which allow free-of-charge interchange between transport modes in a single trip. In 2012, it was announced that the ATM was planning to upgrade the current magnetic stripe-based technology used on the STI to a contactless smart card validation system known as T-mobilitat, reducing all the existing ATM cards to one.