The Société nationale des chemins de fer français (French pronunciation: ​[sɔsjete nɑsjɔnal de ʃ(ə)mɛ̃ d(ə) fɛʁ fʁɑ̃sɛ]; abbreviated as SNCF [ɛs‿ɛn se ɛf]; French for "National society of French railroads") is France's national state-owned railway company. Founded in 1938, it operates the country's national rail traffic along with Monaco, including the TGV, on France's high-speed rail network. Its functions include operation of railway services for passengers and freight (through its subsidiaries SNCF Voyageurs and Rail Logistics Europe), as well as maintenance and signalling of rail infrastructure (SNCF Réseau). The railway network consists of about 35,000 km (22,000 mi) of route, of which 2,600 km (1,600 mi) are high-speed lines and 14,500 km (9,000 mi) electrified. About 14,000 trains are operated daily.

In 2010 the SNCF was ranked 22nd in France and 214th globally on the Fortune Global 500 list. It is the main business of the SNCF Group, which in 2020 had €30 billion of sales in 120 countries. The SNCF Group employs more than 275,000 employees in France and around the world. Since July 2013, the SNCF Group headquarters are located in a Parisian suburb at 2 Place aux Étoiles in Saint-Denis. The president of SNCF Group has been Jean-Pierre Farandou since 2019.