Patani, or the Sultanate of Patani (Jawi: كسلطانن ڤطاني) was a Malay sultanate in the historical Pattani Region. It covered approximately the area of the modern Thai provinces of Pattani, Yala, Narathiwat and part of the Malaysian state of Kelantan. The 2nd–15th century state of Langkasuka and the 6th–7th century state of Pan Pan may have been related.

The golden age of Patani started during the reign of the first of its four successive queens, Raja Hijau (The Green Queen), who came to the throne in 1584 and was followed by Raja Biru (The Blue Queen), Raja Ungu (The Purple Queen) and Raja Kuning (The Yellow Queen). During this period the kingdom's economic and military strength was greatly increased to the point that it was able to fight off four major Siamese invasions. It had declined by the late 17th century and it was invaded by Siam in 1786, which eventually absorbed the state after its last raja was deposed in 1902.

An early kingdom in the Patani area was the Hindu-Buddhist Langkasuka, founded in the region as early as the 2nd century. It appeared in many accounts by Chinese travellers, among them was the Buddhist pilgrim Yijing. The kingdom drew trade from Chinese, Indian, and local traders as a stopping place for ships bound for, or arriving from, the Gulf of Thailand. Langkasuka reached its greatest economic success in the 6th and 7th centuries and afterward declined as a major trade center. Political circumstances suggest that by the 11th century, Langkasuka was no longer a major port visited by merchants. However, much of the decline may be due to the silting up of the waterway linking it to the sea.

The most substantial ruins believed to be ancient Langkasuka have been found in Yarang located approximately 15 kilometres from the sea and the current city of Pattani. How or when Langkasuka was replaced by Patani is unknown. Patani is not mentioned in the Javanese text Nagarakretagama written in 1365, but places such as Langkasuka, Sai and Kelantan are, which may indicate Patani had yet to be founded in this period. Hikayat Patani indicates that the immediate predecessor of Patani was Kota Mahligai ("the citadel town") whose ruler founded Patani, perhaps some time between 1350 and 1450. This Patani was located in Keresik (name in Malay) or Kru Se (in Thai), a few kilometers to the east of the current city.

However, some think Patani was the same country known to the Chinese as Pan Pan.

The region had been subject to Siamese control for some time. In the 14th century, King Ram Khamhaeng the Great (c. 1239 – 1317) of Sukhothai occupied Nakhon Si Thammarat and its vassal states which would include Patani if it had existed at that date. The Siamese Ayutthaya Kingdom also conquered the isthmus during the 14th century, and controlled many smaller vassal states in a self-governing system in which the vassal states and tributary provinces pledged allegiance to the king of Ayutthaya, but otherwise ran their own affairs.

The Hikayat Patani suggests the name Patani means "this beach" which is "pata ni" (pantai ini) in the local Malay language. In this story, a ruler went hunting one day and saw a beautiful white mouse-deer the size of a goat, which then disappeared. He asked his men where the animal had gone, and they replied: "Pata ni lah!" This ruler then ordered a town be built where the mouse-deer had disappeared it was then named after "this beach". The founder is named in some sources as either Sri Wangsa or Phaya Tunakpa, a ruler of Kota Malikha or Kota Mahligai. The first ruler of Patani (some sources say his son) later converted to Islam and took the name Sultan Ismail Shah or Mahmud Shah.

The Hikayat Patani also mentions that the ruler met an old fisherman there, who replied "Encik Tani" ("Mister Tani") when asked his name. An alternative suggestion is therefore that the town was named after the old fisherman, Pak Tani (Father Tani), who was sent by a king from the interior to survey the coast, to find a place for an appropriate settlement. After he established a successful fishing outpost, other people moved to join him. The town that grew into a prosperous trading center would continue to bear his name.^{[citation needed]}