London Paddington, also known as just Paddington, is a member of the London station group and London Underground station complex, located on Praed Street in the Paddington area. The site has been the London terminus of services provided by the Great Western Railway and its successors since 1838. Much of the main line station dates from 1854 and was designed by Isambard Kingdom Brunel. In the year ending March 2024, it was the second busiest station in Great Britain after London Liverpool Street, with an estimated 66.9 million entries and exits.

Paddington is the London terminus of the Great Western Main Line; passenger services are primarily operated by Great Western Railway, which provides commuter and regional passenger services to west London and the Thames Valley region, as well as long-distance intercity services to South West England and South Wales. The station is the eastern terminus for Heathrow Express. Elizabeth line services run through Paddington westwards to Reading, Heathrow Terminal 5, and Heathrow Terminal 4, and eastwards to Abbey Wood and Shenfield. Situated in fare zone 1, it has two separate London Underground stations: one for the Bakerloo, Circle and District lines; the other for the Circle and Hammersmith & City lines. It is one of 11 London stations managed directly by Network Rail.

The station has been perennially popular for passengers and goods, particularly milk and parcels. Major upgrades took place in the 1870s, the 1910s and the 1960s, each trying to add additional platforms and space while trying to preserve the existing services and architecture as much as possible. Paddington was first served by London Underground trains in 1863, as the original western terminus of the Metropolitan Railway, the world's first underground railway. In the 20th century, suburban and commuter services appeared at Paddington as the urban sprawl of London moved westwards. Despite the numerous upgrades and rebuilding, plus damage sustained in particular during World War II, Brunel's original design is still recognisable.

The station complex is bounded at the front by Praed Street and at the rear by Bishop's Bridge Road, which crosses the station throat on Bishop's Bridge. On the west side of the station is Eastbourne Terrace, while the east side is bounded by the Paddington arm of the Grand Union Canal. The station is in a shallow cutting, a fact obscured at the front by a hotel building, but which can be clearly seen from the other three sides. To the north of the station is the Westway, to the northeast is Edgware Road, and to the east and southeast is the London Inner Ring Road.

The surrounding area is partly residential, and includes the major St Mary's Hospital, restaurants and hotels. Until recently there was little office accommodation in the area, and most commuters interchanged between National Rail and the London Underground to reach workplaces in the West End or the City. However, recent redevelopment of derelict railway and canal land, marketed as Paddington Waterside, has resulted in new office complexes nearby.

The station is in London fare zone 1. In addition to the Underground stations at Paddington, Lancaster Gate station on the Central line is a short walk away to the south. A little further to the south lie the conjoined parks of Hyde Park and Kensington Gardens.

The narrow busy section of the incoming main railway line between Ladbroke Grove and Paddington station is known as Paddington Throat among some engineers.

The National Rail station is officially named London Paddington, a name commonly used outside London but rarely by Londoners, who call it just Paddington, as on the London Underground map. This same practice applies to all the London mainline rail termini, except London Bridge. Parts of the station, including the main train shed, date from 1854, when it was built by Isambard Kingdom Brunel as the London terminus for the Great Western Railway (GWR). It is one of eleven stations in London managed by Network Rail.