Temple Bar was the principal ceremonial entrance to the City of London from the City of Westminster. In the middle ages, London expanded city jurisdiction beyond its walls to gates, called ‘bars’, which were erected across thoroughfares. To the west of the City of London, the bar was located adjacent to the area known as the Temple. Temple Bar was situated on the historic royal ceremonial route from the Tower of London to the Palace of Westminster, the two chief residences of the medieval English monarchs, and from the Palace of Westminster to St Paul's Cathedral. The road east of the bar within the City was Fleet Street, while the road to the west, in Westminster, was The Strand.

At the bar, the Corporation of the City of London erected a barrier to regulate trade into the City. The 19th century Royal Courts of Justice are located to its north, having been moved from Westminster Hall. To its south is Temple Church, along with the Inner Temple and Middle Temple Inns of Court. As the most important entrance to the City of London from Westminster, it was formerly long the custom for the monarch to halt at the Temple Bar before entering the City of London, in order for the Lord Mayor to offer the Corporation's pearl-encrusted Sword of State as a token of loyalty.

'Temple Bar' strictly refers to a notional bar or barrier across the route, but it is also used to refer to the 17th-century ornamental, English Baroque arched gateway building attributed Christopher Wren, which spanned the roadway at the bar for two centuries. After Wren's gateway was removed in 1878, the Temple Bar Memorial topped by a dragon symbol of London, and containing an image of Queen Victoria, was erected to mark the location. Wren's archway was preserved and was re-erected in 2004 in the City, in a redeveloped Paternoster Square next to St Paul's Cathedral. In September 2022, the preserved Wren gateway and an adjacent building were officially opened by the Duke of Gloucester as the home of the Worshipful Company of Chartered Architects.