London Transport (LT) was the public name and brand used by a series of public transport authorities in London, England, from 1933. Its most recognizable feature was the bar-and-circle 'roundel' logo. With its origins in the Underground Electric Railways Company of London (UERL), the brand was first used by the London Passenger Transport Board (LPTB) to unify the identity of the previously separately owned and managed London Underground, Metropolitan Railway, bus and tram services. The London Transport brand was extended under the direction of Frank Pick to all aspects of transport operation including poster designs, tickets, train livery, seat upholstery and the station architecture of Charles Holden. When public transport operation was taken over by Transport for London (TFL) from London Regional Transport (LRT) in 2000, the London Transport brand was discontinued and replaced with Transport for London's own branding, which incorporates many features of the London Transport brand including the 'roundel' symbol and the Johnston font.

The London Passenger Transport Board was the organisation responsible for local public transport in London and its environs from 1933 to 1948. In common with all London transport authorities from 1933 to 2000, the public name and brand was London Transport.