Rail transport in Greece has a history which began in 1869, with the completion of the then Athens & Piraeus Railway. From the 1880s to the 1920s, the majority of the network was built, reaching its heyday in 1940. From the 1950s onward, the railway system entered a period of decline, culminating in the service cuts of 2011. Ever since the 1990s, the network has been steadily modernized, but still remains smaller than its peak length. The operation of the Greek railway network is split between the Hellenic Railways Organisation (OSE), which owns and maintains the rail infrastructure; GAIAOSE, which owns the building infrastructure and the former OSE rolling stock, Hellenic Train; and other private companies that run the trains on the network. Greece is a member of the International Union of Railways (UIC). The UIC Country Code for Greece is 73.

The Hellenic Railways Organisation or OSE is the Greek national railway company which owns, maintains and operates all railway infrastructure in Greece with the exception of Athens' rapid transit lines. Train services on these lines are run by Hellenic Train S.A., a former OSE subsidiary, Rail Cargo Logistics Goldair, Pearl and Grup Feroviar Român.