The Royal Pavilion (also known as the Brighton Pavilion) and its surrounding gardens form a Grade I listed former royal residence located in Brighton, England. Beginning in 1787, it was built in three stages as a seaside retreat for George, Prince of Wales, who became the Prince Regent in 1811, and King George IV in 1820. It is built in the Indo-Saracenic style prevalent in India for most of the 19th century. The current appearance, with its Mughal inspired features such as bulbous domes, chhatri-topped minarets and cusped arches, is the work of the architect John Nash, who extended the building starting in 1815. George IV's successors William IV and Victoria also used the Pavilion, but Queen Victoria decided that Osborne House should be the royal seaside retreat, and the Pavilion was sold to the city of Brighton in 1850.

The Prince of Wales, who later became King George IV, first visited Brighton in 1783, at the age of 21. The seaside town had become fashionable as a result of the residence of George's uncle, Prince Henry, Duke of Cumberland, whose tastes for fine cuisine, gambling, the theatre, and general fast living the young prince shared, and with whom he lodged in Brighton at Grove House. In addition, the Prince of Wales was advised by his physician that the seawater and fresh air would be beneficial for his gout. In 1786, under a financial cloud with investigations by Parliament for the extravagances incurred in building Carlton House, London, the prince rented a modest, erstwhile farmhouse facing the Old Steine, a grassy area of Brighton used as a promenade by visitors. Remote from the royal court in London, the pavilion was a discreet location for the prince to enjoy private liaisons with his long-time companion, Maria Fitzherbert. The prince had wished to marry her, and did so in secrecy as her Roman Catholic religion prohibited his marrying her under the Royal Marriages Act 1772.

In 1787, the prince commissioned the designer of Carlton House, Henry Holland, to enlarge the existing building. It became one wing of the Marine Pavilion, flanking a central rotunda, which contained three main rooms: a breakfast room, dining room, and library, fitted out in Holland's French-influenced neoclassical style, with decorative paintings by Biagio Rebecca. In 1801–02, the pavilion was enlarged with a new dining room and conservatory, to designs of Peter Frederick Robinson, who worked in Holland's office. The Prince also purchased land surrounding the property, on which a grand riding school and stables were built in an Indian style in 1803–08, to designs by William Porden, along with a famous onion garden to feed the Prince's well-known addiction. These provided stabling for 60 horses and dwarfed the Marine Pavilion.

Between 1815 and 1822, the designer John Nash redesigned and greatly extended the pavilion, and it is his work that is still visible today.

Nash brought to Brighton structural innovations pioneered in his earlier work on the Rotunda at Carlton House, particularly in the construction of the Music and Banqueting Rooms' distinctive tented roofs. These employed laminated timber construction techniques developed by Nash and his assistant William Nixon for the Carlton House Rotunda in 1814—a pioneering system using specialised iron connectors that allowed the roofs to span large ceremonial spaces without central supporting columns. Nixon, who had designed the Rotunda's innovative divided tie-beam truss system, continued working with Nash at Brighton Pavilion until his death in 1826. The palace is striking in the middle of Brighton, for its unique Indo-Islamic exterior. The fanciful interior design, primarily by Frederick Crace and the little-known decorative painter Robert Jones, was heavily influenced by both Chinese and Indian fashion (with Mughal and Islamic architectural elements). The architectural design of the Royal Pavilion has drawn comparisons to the Taj Mahal due to its prominent onion domes, minarets, and Indo-Saracenic influences. While the Taj Mahal is a Mughal mausoleum built in the 17th century, the Pavilion was designed in the early 19th century by John Nash as a seaside retreat for King George IV. Despite their different historical and cultural contexts, the Pavilion's exterior bears a visual resemblance to the iconic Indian monument, reflecting the 19th-century British fascination with South Asian architecture. It is a prime example of the exoticism that was an alternative to more classicising mainstream taste in the Regency style.

After the death of George IV in 1830, his successor William IV also stayed in the pavilion on his frequent visits to Brighton. Queen Victoria, however, disliked Brighton and the lack of privacy at the pavilion. Brighton became accessible to Londoners by rail in 1841, increasing its popularity with the masses. In addition, the pavilion was cramped for her growing family. Famously, Queen Victoria disliked the constant attention she attracted in Brighton, saying "the people here are very indiscreet and troublesome".

She purchased an estate and land that was redeveloped for Osborne House on the Isle of Wight, which became the summer home of the royal family. After her last visit to Brighton in 1845, the government planned to sell the building and grounds. The Brighton Improvement Commissioners and the Brighton Vestry successfully petitioned the government to sell the Pavilion to the town for £53,000 in 1850 under the Brighton Royal Pavilion Act 1850 (13 & 14 Vict. c. v). The sale helped fund furnishing of Osborne House.

In 1860, the adjacent royal stables were converted to a concert hall, now known as the Brighton Dome. The town used the building as assembly rooms. Many of the Pavilion's original fixtures and fittings were removed on the order of the royal household at the time of the sale, most ending up either in Buckingham Palace or Windsor Castle. In the late 1860s, Queen Victoria returned to Brighton large quantities of unused fittings. George V and Queen Mary returned more furnishings after the First World War.