The Rome Metro (Italian: Metropolitana di Roma) is a rapid transit system that operates in Rome, Italy. It started operation in 1955, making it the oldest in the country.

The Metro comprises three lines―A (orange), B (blue) and C (green)―which operate on 62 km (39 mi) of route, serving 74 stations. It has a daily ridership of approximately 820,000 passengers and has an annual traffic of approximately 320 million passengers.

In addition to the Metro, the centre of Rome and its urban area are served by eight FL lines (672 km (417.5 mi) with 131 stations) that surround Rome and the Lazio region, six tram lines (36 km (22 mi) with 192 stations), three commuter urban lines (135 km (83.8 mi) with 57 stations), the Leonardo Express, which connects Roma Termini, the central station of the city, to the Leonardo da Vinci Airport of Fiumicino, and the Civitavecchia Express, which connects the city to the main port of Rome, the Port of Civitavecchia. Network extensions are currently under construction on Line C (station Venezia is expected to open in 2033). There are further projects for Line A, Line B, Rome–Giardinetti and for the suburban rail system. The entire transport system in Rome uses the Metrebus integrated tariff system (an acronym composed of the words "Metro", "Treno" and "Bus"), which can be used within the limits of the Municipality of Rome and within the limits of the urban tariff.

Line B was the first metro line inaugurated in the system, and the first official metro in Italy, but the names 'A' and 'B' were only added when the second line opened 25 years after the first. Inaugurated in post-war Italy in 1955 during the reconstruction and on the verge of the Italian economic miracle, it was designed and built for the 1942 universal exhibition (Esposizione Universale Roma, which is now the current business centre of Rome) desired by the fascist regime, which never took place due to the outbreak of the World War II.

Line A runs from the southeastern suburbs of Rome, then along the northeast section of downtown, and then to the northern section of the city, near Vatican City. It connects with Line B, along with many other national and regional rail services, at Termini, and with Line C at San Giovanni. It has 27 stations, with terminals at Battistini and Anagnina. It is identified by the colour orange.

Line A was the second line built in Rome. Approval was given for the construction of the city's second Metro line in 1959.

Work on Line A began in 1964 in the Tuscolana area, but it experienced a series of delays because the originally planned cut-and-cover method of construction posed serious problems for road traffic in southeast Rome. Work on the Metro was suspended and began again five years later, using bored tunnels, which partially resolved the traffic problems but caused numerous claims for compensation for vibrations caused by the machines. Work was also frequently interrupted by archaeological finds made during the excavations, particularly near Piazza della Repubblica.^{[citation needed]}

Line A entered service in February 1980. In the late 1990s, it was extended from Ottaviano, in the Prati district, to Battistini to the west.