The Barbican Estate, or Barbican, is a residential complex of around 2,000 flats, maisonettes and houses in central London, England, within the City of London. It is in an area once devastated by World War II bombings and densely populated by financial institutions, 1.4 miles (2.2 km) north east of Charing Cross. Originally built as rental housing for middle- and upper-middle-class professionals, it remains an upmarket residential estate. It contains, or is adjacent to, the Barbican Centre, the Museum of London, the Guildhall School of Music and Drama, the Barbican public library, the City of London School for Girls and a YMCA (now closed), forming the Barbican Complex.

The Barbican Complex is a prominent example of British brutalist architecture and is Grade II listed as a whole, with the exception of the former Milton Court, which once contained a fire station, medical facilities and some flats but was demolished to allow the construction of a new apartment tower—named The Heron—which also provides additional facilities for the Guildhall School of Music and Drama.

The main fort of Roman London was built between 90 and 120 AD south-east of where the Museum of London now stands at the corner of London Wall and Aldersgate Street. Around 200 AD, walls were built around the city that incorporated the old fort, which became a grand entrance known as Cripplegate. The word barbican comes from the Low Latin word Barbecana, which referred to a fortified outpost or gateway, such as an outer defence of a city or castle or any tower situated over a gate or bridge that was used for defence purposes. In this case there seems to have been a Roman specula or watchtower in front of the fort from numbers 33–35 onwards on the north side of the street formerly called Barbican (now the west end of Beech St), which was later incorporated into the fortifications north of the wall. The Normans called it the Basse-cour or Base Court, synonymous with the modern word "bailey" and still applied to the outer courtyard of Hampton Court Palace.

The Base Court continued to serve a military function during the reign of Edward I, but Edward III gave it to Robert d'Ufford, 1st Earl of Suffolk, who made it his London home. By the 16th century it had passed to Charles Brandon, 1st Duke of Suffolk. Brandon married his ward Catherine Willoughby, daughter of María de Salinas, who had been a confidante and lady-in-waiting of Catherine of Aragon, and after his death the building was retained by the Willoughby family. The original Base Court seems to have been destroyed and the large building that replaced it was called Willoughby House, a name revived for part of the modern development. The house was later owned by Thomas Egerton, Lord Ellesmere, and later named Bridgewater House after the title bestowed on John Egerton in 1617.

The Barbican terrace blocks and residences, including the green garden in the centre, are laid on an area just outside the city fortifications, to the north west of the surviving London Wall and bastions. Most of the residences and the green square, as well as some of the area to the south, currently occupied by the Museum of London, are on an area that was previously the cemetery serving the London Jewish community before their expulsion. Records of transactions of the time show that the cemetery had been expanded several times through the acquisition of property by the Jews between 1268 and 1290. The Jews were expelled from England in 1290, and on 12 July 1291 Edward I granted the site of the cemetery to Master William de Montford, who was Dean of St Paul's but seems to have held this land privately. Archaeological excavations were undertaken on part of the cemetery site prior to construction of the Barbican and the results of these investigations were published in Transactions of the Jewish Historical Society of England (JHSE) in 1961.

During World War II the City suffered serious damage and loss of life. The Cripplegate ward was virtually demolished and by 1951 the resident population of the City stood at 5,324, of whom 48 lived in Cripplegate. Discussions began in 1952 about the future of the site, and the decision to build new residential properties was taken by the Court of Common Council on 19 September 1957.

To accommodate the estate, 500 metres (550 yards) of the Metropolitan line was realigned between Barbican and Moorgate stations between 1963 and 1965.

The estate was built between 1965 and 1976, on a 35-acre (14 ha) site. The complex was designed by architects Chamberlin, Powell and Bon, whose first work was the ground-breaking Golden Lane Estate immediately north of the Barbican. Unlike its northern neighbour, however, the Barbican Estate was not social housing. Rather, it was designed and built for affluent City professionals and their families, with all flats let out at commercial rents by the Corporation of London. To help let out the flats, brochures were produced advertising the Barbican Estate as containing the perfect residences for well-heeled professionals and international businesspeople.