The Metropolitan Railway (also known as the Met) was a passenger and goods railway that served London from 1863 to 1933, its main line heading north-west from the capital's financial heart in the City to what were to become the Middlesex suburbs. Its first line connected the main-line railway termini at , , and to the City. The first section was built beneath the New Road using the "cut-and-cover" method between Paddington and King's Cross and in tunnel and cuttings beside Farringdon Road from King's Cross to near Smithfield, near the City. It opened to the public on 10 January 1863 with gas-lit wooden carriages hauled by steam locomotives, the world's first underground railway.

Metropolitan railway can refer to:

• Metropolitan line, part of the London Underground
• Metropolitan Railway, (historical) the first underground railway to be built in London
• Metropolitan District Railway, (historical) the second underground railway to be built in London
• The railway system known as rapid transit