Piccadilly Circus is a famous traffic intersection and public space of London's West End in the City of Westminster. Built in 1819 to connect Regent Street with the major shopping street of Piccadilly (the "circus" refers to "circular open space at a street junction"), it now links directly to the theatres on Shaftesbury Avenue as well as the Haymarket, Coventry Street (onwards to Leicester Square) and Glasshouse Street. The Circus is close to major shopping and entertainment areas in a central location at the heart of the West End. Its status as a major traffic intersection has made Piccadilly Circus a busy meeting point and a tourist attraction in its own right.

The Circus is particularly known for its video display and neon signs mounted on the corner building on the northern side, as well as the Shaftesbury memorial fountain and statue known as 'Eros' (sometimes called 'The Angel of Christian Charity', which would be better translated as 'Agape', but formally 'Anteros' - see below). It is surrounded by several noted buildings, including the London Pavilion and Criterion Theatre. Directly underneath the plaza is the London Underground station Piccadilly Circus.

The Piccadilly Circus station on the London Underground is located directly beneath Piccadilly Circus itself, with entrances at every corner. It is one of the few stations which have no associated buildings above ground and is fully underground

The station is on the Piccadilly Line between Green Park and Leicester Square, and the Bakerloo Line between Charing Cross and Oxford Circus.