The Orient Express was a long-distance passenger train service created in 1883 by the Belgian company Compagnie Internationale des Wagons-Lits (CIWL) that operated until 2009. The train traveled the length of continental Europe and into western Asia, with terminal stations in London in the northwest and Athens or Istanbul in the southeast.

The route and rolling stock of the Orient Express changed many times. Several routes in the past concurrently used the Orient Express name, or slight variations. Although the original Orient Express was simply a normal international railway service, the name became synonymous with intrigue and luxury rail travel. The two city names most prominently associated with the Orient Express are Paris and Istanbul, the original endpoints of the timetabled service. The Orient Express was a showcase of luxury and comfort at a time when travelling was still rough and dangerous.In 1977, the Orient Express stopped serving Istanbul. Its immediate successor, a through overnight service from Paris to Bucharest, was later cut back in 1991 to Budapest, and in 2001 was again shortened to Vienna, before departing for the last time from Paris on Friday 8 June 2007. After this, the route, still called the "Orient Express", was shortened to start from Strasbourg instead, occasioned by the inauguration of the LGV Est which afforded much shorter travel times from Paris to Strasbourg. The new curtailed service left Strasbourg at 22:20 daily, shortly after the arrival of a TGV from Paris, and was attached at Karlsruhe to the overnight sleeper service from Amsterdam to Vienna.

On 14 December 2009, the Orient Express ceased to operate and the route disappeared from European railway timetables, reportedly a "victim of high-speed trains and cut-rate airlines". Since 13 December 2021, an ÖBB Nightjet again runs three times per week on the Paris-Vienna route, although not branded as Orient Express. The Venice-Simplon Orient Express train, a private venture by Belmond using original CIWL carriages from the 1920s and 1930s, continues to run from London to Venice and to other destinations in Europe, including the original route from Paris to Istanbul.