The Moscow Metro (Russian: Моско́вский метрополите́н, tr. Moskovsky metropoliten; IPA: [mɐˈskofskʲɪj mʲɪtrəpəlʲɪˈtɛn]) is a rapid transit system serving Moscow and the neighbouring town of Krasnogorsk. Opened in 1935 with one 11-kilometre (6.8 mi) line and 13 stations, it was the first underground railway system in the Soviet Union. As of 2011, the Moscow Metro has 185 stations and its route length is 305.7 kilometres (190.0 mi). The system is mostly underground, with the deepest section 84 metres (276 ft) below ground at the Park Pobedy station. The Moscow Metro is the world's second most heavily used rapid transit system after Tokyo's twin subway.

The Moscow Metro is a state-owned enterprise. Its total length is 305.5 km (189.8 mi) and consists of 12 lines and 185 stations. The average daily passenger traffic is 6.6 million. Ridership is highest on weekdays (when the Metro carries over 7 million passengers per day) and lower on weekends. Each line is identified according to an alphanumeric index (usually consisting of a number), a name and a colour. Voice announcements refer to the lines by name. A male voice announces the next station when traveling towards the centre of the city, and a female voice when going away from it. On the circle line the clockwise direction has a male announcer for the stations, while the counter-clockwise direction has a female announcer. The lines are also assigned specific colours for maps and signs. Naming by colour is frequent in colloquial usage, except for the very similar shades of green assigned to the Kakhovskaya Line (route 11), the Zamoskvoretskaya Line (route 2), the Lyublinsko-Dmitrovskaya Line (route 10) and the Butovskaya Line (route L1).

Moscow ( /ˈmɒskaʊ/ or /ˈmɒskoʊ/; Russian: Москва́, tr. Moskva; IPA: [mɐˈskva] ( listen)) is the capital and the most populous federal subject of Russia. The city is a major political, economic, cultural and scientific center of Russia and the continent. Moscow is the northernmost megacity on Earth, the most populous city in Europe, and the 6th largest city proper in the world. Its population, according to the results of the 2010 Census, is 11,503,501. Based on Forbes 2011, Moscow has the largest community of billionaires in the world.

Moscow is situated on the Moskva River in the Central Federal District of European Russia. In the course of its history the city has served as the capital of a progression of states, from the medieval Grand Duchy of Moscow and the subsequent Tsardom of Russia to the Soviet Union. Moscow is the site of the Moscow Kremlin, an ancient fortress that is today the residence of the Russian President and of the executive branch of the Government of Russia. The Kremlin is also one of several World Heritage Sites in the city. Both chambers of the Russian parliament (the State Duma and the Federation Council) also sit in Moscow.