Bristol, the largest city in South West England, has an eclectic combination of architectural styles, ranging from the medieval to 20th century brutalism and beyond. During the mid-19th century, Bristol Byzantine, an architectural style unique to the city, was developed, and several examples have survived. Buildings from most of the architectural periods of the United Kingdom can be seen throughout Bristol. Parts of the fortified city and castle date back to the medieval era, as do some churches dating from the 12th century onwards. Outside the historical city centre there are several large Tudor mansions built for wealthy merchants. Almshouses and public houses of the same period survive, intermingled with areas of more recent development. Several Georgian-era squares were laid out for the enjoyment of the middle class. As the city grew, it merged with its surrounding villages, each with its own character and centre, often clustered around a parish church.

The construction of the city's Floating Harbour, taking in the wharves on the River Avon and Frome, provided a focus for industrial development and the growth of the local transport infrastructure. Key elements of which include the Isambard Kingdom Brunel designed Clifton Suspension Bridge and Temple Meads terminus; the latter served from 2002 to 2009 as the British Empire and Commonwealth Museum, but is now closed. The 20th century saw further expansion of the city, the growth of the University of Bristol and the arrival of the aircraft industry. During World War II, the city centre was extensively bombed in the Bristol Blitz. The redevelopment of shopping centres, office buildings, and the harbourside continues to this day.

11th – 14th century: Medieval architecture

Defensive The city was defended in medieval times by Bristol Castle, a Norman fortification built on the site of a wooden predecessor. The castle played a key role in the civil wars that followed the death of Henry I. Stephen of Blois reconnoitred Bristol in 1138 and claimed that the town was impregnable. After Stephen's capture, in 1141, he was imprisoned in the castle. The castle was later taken into royal hands, and Henry III spent lavishly on it, adding a barbican before the main west gate, a gate tower, and a magnificent hall. By the 16th century, the castle had fallen into disuse, but the city authorities had no control over royal property, and so the castle became a refuge for lawbreakers. In 1630, the city purchased the castle; Oliver Cromwell ordered its destruction in 1656. An area outside the castle, known as Old Market, was used as a mustering point for troops. It later became a market for the country people to set up stalls and sell their wares. Old Market was also the site of an autumn fair. The market may have existed as early as the 12th century, and was the site of the first suburb outside the city walls. It had side roads which could accommodate the traffic on market days.

The city had extensive walls built by Geoffrey de Montbray, Bishop of Coutances. These have now largely disappeared, although parts remain on properties in King Street. A gateway in the old wall can now be seen under the tower of the Church of St John the Baptist.

Religious The earliest surviving church in Bristol is St James' Priory in Horsefair, Whitson Street. It was founded in 1129, as a Benedictine priory, by Robert Rufus. The 12th century also saw the founding of All Saints and St Philip and Jacob churches. Temple Church, now in ruins, was built on the site of the oval church of the Knights Templar, a Christian military order forcibly disbanded in 1312. At this time, the church was rebuilt to serve as a parish church.

Bristol Cathedral was founded as St Augustine's Abbey in 1140 by Robert Fitzharding, along with its associated school, with the building works continuing in the Gothic style until about 1420. St Mark's Church was built around 1220. Soon after, the foundations were laid for Holy Trinity Church in Westbury on Trym. The 12th century also saw the foundation of St Mary Redcliffe, renowned as one of the finest examples of the 15th century Perpendicular style, and the tallest building in the city. Elizabeth I, on a visit to the city in 1574, described it as the "fairest, goodliest and most famous parish church in England". These 12th-century churches were followed in the 14th century by the construction of Church of St John the Baptist and St Stephen's Church. Westbury College was a 13th-century College of Priests located in Westbury-on-Trym. A gatehouse was added in the 15th century, which is now a National Trust property.

Tudor period

The Tudor period, which lasted from the late 15th century into the early 17th century, saw the increasing development of the city's mercantile class, whose members gained much of their wealth from the trade passing through Bristol Harbour. They built houses financed by their trade, and reflective of their wealth and status; such as Ashton Court, essentially a country house although only two miles from the centre of the city, or Red Lodge in the city itself, built in 1580 for John Yonge as the lodge for a great house that once stood on the site of the present Bristol Beacon.

During the English Civil War, the Royal Fort was considered the strongest part of Bristol's defences, and it was to the fort that the Royalists retreated when they found themselves under siege from the Parliamentarians. It fell to the parliamentary forces in 1645 and was subsequently demolished. St Nicholas's Almshouses were built in 1652 to provide care for the poor. Several public houses were also built in this period, including the Llandoger Trow on King Street and the Hatchet Inn. More churches were built, including St Michael on the Mount Without. It served the St Michaels hill area, one of the first areas outside the city walls to be colonised by the wealthy merchants who were by then trying to escape the overcrowded and unhealthy conditions in the city centre. The city was by this time beginning to expand rapidly beyond its traditional city walls, and the surrounding villages were starting to become suburbs, such as the villages of Horfield and Brislington. Both had their own churches, the Church of the Holy Trinity with St Edmund and St Lukes.

17th – 19th century: Style revivals

Stuart period

The Stuart or English Baroque period (1666–1713) saw more expansion of the city. Large mansions such as Kings Weston House and Goldney Hall were constructed. The needs of the poor and destitute became the responsibility of institutions such as Colstons and the Merchant Venturers Almshouses. The King Street area was developed outside the "Back Street Gate" of the city, home to the King William and Naval Volunteer Public Houses. The nearby Queen Square was planned during this era.

In 1669, a series of four flights of steps, now called Christmas Steps, was constructed to replace a steep, muddy, and narrow street formerly known as Queene Street. Many of the larger houses of this period, including Queen Square, were built for merchant families who were heavily involved in the slave triangle, importing goods from slave plantations. A few African and creole (American- and Caribbean-born) slaves came to Bristol as servants.

Georgian period

In 1732, John Strachan built Redland Court for John Cossins. It now forms one of the buildings making up Redland High School for Girls. In 1760, the Bristol Bridge Act was carried through parliament by the Bristol MP Sir Jarrit Smyth. That led to the demolition of St Nicholas's Gate, along with much of the original St Nicholas Church. The original bridge was a medieval wooden structure, lined with houses on both sides.

A 17th-century illustration shows that these were five stories high, including the attic rooms, and that they overhung the river much as Tudor houses would overhang the street. At the time of the Civil War the bridge was noted for its community of goldsmiths, who may have been attracted by the unusually secure premises. The current St Nicholas church was rebuilt in 1762–9 by James Bridges and Thomas Paty, who rebuilt the spire. Part of the old church and town wall survives in the 14th century crypt. The 1766 Theatre Royal, which claims to be the oldest continually operating theatre in England, joined with the Coopers' Hall, from 1744 and designed by architect William Halfpenny, to form the Bristol Old Vic.

During the period of Georgian architecture () the main architects and builders working in Bristol were James Bridges, John Wallis, and Thomas Paty with his sons John and William Paty. They put up hundreds of new buildings, reflecting the increased prosperity that came with the new Floating Harbour and trade based at The Exchange, built in 1741–43 by John Wood the Elder. Their early work included the Royal Fort, Blaise Castle House and Arno's Court estate, with the associated Arno's Court Triumphal Arch and Black Castle Public House. More modest terraces and squares grew up in the new suburbs such as Hotwells and north into Clifton, including 7 Great George Street, now the Georgian House Museum. It was built around 1790 for John Pinney a successful sugar merchant, and is believed to be the house where the poets William Wordsworth and Samuel Taylor Coleridge first met. It was also home to Pinney's slave, Pero, after whom Pero's Bridge at Bristol Harbour is named.

In addition to evidence of the wealth brought by the slave trade there are several significant links to the abolitionists. Bristol's Hannah More was an influential member of the Society for Effecting the Abolition of the African Slave Trade. In the Seven Stars Public House Thomas Clarkson collected evidence for William Wilberforce on the cruelty of the trade in humans. Bristol Cathedral contains several memorials to people active in the abolition cause, including a bust of Robert Southey. John Wesley opposed the trade in humans and in 1774 his sermon at the New Room against slavery was disturbed by explosion. Several plays adopted by the abolitionists were performed at the Bristol Old Vic, including Oroonoko, the story of an enslaved African and The Padlock, which was praised by Clarkson for its importance to the abolition cause.

Several residential squares with terraces of three-storey houses were laid out around central gardens. An example is Portland Square, which was built between 1789 and 1820, and is now largely occupied by offices. In the 1830s, much of Queen Square was rebuilt following damage caused during the Bristol Riots, and to the north of the city, Kings Square. The most fashionable areas were at the top of the hill, as in wet weather the cesspits overflowed down the hill. Further development, though in a less formal manner, continued along the radial roads to Stokes Croft and Cheltenham, towards Horfield and in the St Phillips, Redcliffe and Bedminster areas. Religious needs in the expanding city were met for several denominations with Redland Chapel and other Church of England buildings appearing, including Christ Church and St Werburghs. Whitefield's Tabernacle, Kingswood was the first Methodist chapel and a Quaker meeting house known as Quakers Friars was built in 1749.

Regency period