The palace has been the official residence of the Kings of Siam (and later Thailand) since 1782. The king, his court and his royal government were based on the grounds of the palace until 1925. The present monarch, King Bhumibol Adulyadej (Rama IX), currently resides at Chitralada Palace, but the Grand Palace is still used for official events. Several royal ceremonies and state functions are held within the walls of the palace every year.

Construction of the palace began on 6 May 1782, at the order of King Buddha Yodfa Chulaloke (Rama I), the founder of the Chakri Dynasty, when he moved the capital city from Thonburi to Bangkok. Throughout successive reigns, many new buildings and structures were added, especially during the reign of King Chulalongkorn (Rama V). By 1925 the king, the Royal Family and the government were no longer permanently settled at the palace, and had moved to other residences. After the abolition of absolute monarchy in 1932 all government agencies completely moved out of the palace.

In shape, the palace complex is roughly rectangular and has a combined area of 218,400 square metres (2,351,000 sq ft), surrounded by four walls. It is situated on the banks of the Chao Phraya River at the heart of the Rattanakosin Island, today in the Phra Nakhon District. The Grand Palace is bordered by Sanam Luang and Na Phra Lan Road to the north, Maharaj Road to the west, Sanamchai Road to the east and Thai Wang Road to the south.

Rather than being a single structure, the Grand Palace is made up of numerous buildings, halls, pavilions set around open lawns, gardens and courtyards. Its asymmetry and eclectic styles are due to its organic development, with additions and rebuilding being made by successive reigning kings over 200 years of history. It is divided into several quarters: the Temple of the Emerald Buddha; the Outer Court, with many public buildings; the Middle Court, including the Phra Maha Montien Buildings, the Phra Maha Prasat Buildings and the Chakri Maha Prasat Buildings; the Inner Court and the Siwalai Gardens quarter. The Grand Palace is currently partially open to the public as a museum, however it remains a working palace as several royal offices are still situated inside. The palace is one of the most popular tourist attractions in Thailand.

The construction of the Grand Palace began on 6 May 1782, at the order of King Buddha Yodfa Chulaloke (Rama I). Having seized the crown from King Taksin of Thonburi, King Rama I was intent on building a capital city for his new Chakri Dynasty. He decided to move the seat of power from the city of Thonburi, on the west side of the Chao Phraya river, to the east side at Bangkok. The new capital city was turned into an artificial island when canals were dug along the east side. The island was given the name 'Rattanakosin'. The previous royal residence was the Derm Palace, constructed for King Taksin in 1768.

The new palace was built on a rectangular piece of land on the very west side of the island, between Wat Pho to the south, Wat Mahathat to the north and with the Chao Phraya river along the west. This location was previously occupied by a Chinese community, whom King Rama I had ordered to relocate to an area south and outside of the city walls; the area is known today as Yaowarat (Chinatown).

Desperate for materials and short on funds, the palace was initially built entirely out of wood, its various structures surrounded by a simple log palisade. On 10 June 1782, the king ceremonially crossed the river from Thonburi to take permanent residence in the new palace. Three days later on 13 June the king held an abbreviated coronation ceremony, thus becoming the first monarch of the new Rattanakosin Kingdom.[2][5] Over the succeeding years the king began replacing wooden structures with masonry, rebuilding the walls, forts, gates, throne halls and royal residences. This rebuilding included the royal chapel, which would come to house the Emerald Buddha.

To find more material for these constructions, King Rama I ordered his men to go upstream to the old capital city of Ayutthaya, which was destroyed in 1767 during a war between Burma and Siam. They were tasked with the dismantling and removal of as many bricks as they could find, while not removing any from the temples. They began by taking materials from the forts and walls of the city; by the end they had completely levelled the old royal palaces. The bricks were ferried down the Chao Phraya by barges, where they were eventually incorporated into the walls of Bangkok and the Grand Palace itself.  Most of the initial construction of the Grand Palace during the reign of King Rama I was carried out by conscripted or corvée labour. After the final completion of the ceremonial halls of the palace, the king held a full traditional coronation ceremony in 1785.

The layout of the Grand Palace followed that of the Royal Palace at Ayutthaya in location, organization, and in the divisions of separate courts, walls, gates and forts. Both palaces featured a proximity to the river. The location of a pavilion serving as a landing stage for barge processions also corresponded with that of the old palace. To the north of the Grand Palace there is a large field, the Thung Phra Men (now called Sanam Luang), which is used as an open space for royal ceremonies and as a parade ground. There was also a similar field in Ayutthaya, which was used for the same purpose. The road running north leads to the Front Palace, the residence of the Second King of Siam.

The Grand Palace from across the Chao Phraya river, circa 1880
The Grand Palace is divided into four main courts, separated by numerous walls and gates: the Outer Court, the Middle Court, the Inner Court and the Temple of the Emerald Buddha. Each of these court's functions and access are clearly defined by laws and traditions. The Outer Court is situated on the northwestern part of the Grand Palace; within are the royal offices and (formerly) state ministries. To the northeast is the Temple of the Emerald Buddha, the royal chapel and home of the Emerald Buddha. The Middle Court housed the most important state apartments and ceremonial throne halls of the king. The Inner Court, situated at the most southern end of the complex, was reserved only for females, as it housed the king's harem.

In the reign of King Buddha Loetla Nabhalai (Rama II), the total area of the Grand Palace was expanded south, up to the walls of Wat Pho. Previously this area was home to offices of various palace officials. This expansion increased the area of the palace from 213,674 square metres (2,299,970 sq ft) to 218,400 square metres (2,351,000 sq ft). New walls, forts and gates were constructed to accommodate the enlarged compound. Since this expansion, the palace has remained within its walls with new construction and changes being made only on the inside.

The location of the Grand Palace in Bangkok. See below for a more labelled plan of the Palace itself.
In accordance with tradition, the palace was initially referred to only as the Phra Ratcha Wang Luang (พระราชวังหลวง) or 'Royal Palace', similar to the old palace in Ayutthaya. However in the reign of King Mongkut (Rama IV) the name Phra Boromma Maha Ratcha Wang or 'Grand Palace' was first used in official documents. This change of name was made during the elevation of Prince Chutamani (the king's younger brother) to the title of Second King Pinklao in 1851. The proclamation of his title described the royal palace as the 'supreme' (บรม; Borom) and 'great' (มหา; Maha) palace. This title was given in order to distinguish the palace from the Second King's palace (the Front Palace), which was described as the Phra Bovorn Ratcha Wang (พระบวรราชวัง) or the 'glorious' (บวร; Bovorn) palace.

Throughout the period of absolute monarchy, from 1782 to 1932, the Grand Palace was both the country's administrative and religious centre. As the main residence of the monarch, the palace was also the seat of government, with thousands of inhabitants including guardsmen, servants, concubines, princesses, ministers and courtiers. The palace's high whitewashed castellated walls, full of forts and guard posts, mirrored those of the walls of Bangkok itself, and thus the Grand Palace was envisioned as a city within a city. For this reason a special set of Palace Laws were created to govern the inhabitants and to establish hierarchy and order.

By the 1920s a series of new palaces were constructed elsewhere for the king's use; these included the more modern Dusit Palace, constructed in 1903, and Phaya Thai Palace in 1909. These other Bangkok residences began to replace the Grand Palace as the primary place of residence of the monarch and his court. By 1925 this gradual move out of the palace was complete. The growth and centralization of the Siamese state also meant that the various government ministries have grown in size and were finally moved out of the Grand Palace to their own premises. Despite this the Grand Palace remained the official and ceremonial place of residence as well as the stage set for elaborate ancient ceremonies of the monarchy. The end of the absolute monarchy came in 1932, when a revolution overthrew the ancient system of government and replaced it with a constitutional monarchy.

Today the Grand Palace is still a centre of ceremony and of the monarchy, and serves as a museum and tourist attraction as well.