The Banten Sultanate (Sundanese: ᮊᮞᮥᮜ᮪ᮒᮔᮔ᮪ ᮘᮔ᮪ᮒᮨᮔ᮪, كسلطانن بنتن, Kasultanan Banten ) was a Bantenese Islamic trading kingdom founded in the 16th century and centred in Banten, a port city on the northwest coast of Java; the contemporary English name of both was Bantam. It is said to have been founded by Sunan Gunungjati, who had previously founded Cirebon.

Once a great trading centre in Southeast Asia, especially of pepper, the kingdom reached its apogee in the late 16th and mid-17th centuries. By the late 17th century, it was overshadowed by Batavia and was finally annexed to the Dutch East Indies in 1813.

Its core territory now forms the Indonesian province of Banten. Today, in Old Banten, the Great Mosque of Banten is an important destination for tourists and for pilgrims from across Indonesia and from overseas.

Prior to 1526, a settlement called Banten was situated about ten kilometres inland from the coast on the Cibanten River, in what is today a suburb of Serang town. It was known as Banten Girang, meaning "Upper Banten" owing to its location. This town previously was a native Hindu Sundanese principality that was held under the Kingdom of Sunda.

A grandson of the King of Sunda, Sri Baduga Maharaja (also known as Prabu Siliwangi) was an ulama named Sunan Gunungjati (Sharif Hidayatullah). He was part of the educated class of Muslim legal scholars who was educated in the Middle East. In the early 16th century, Gunungjati arrived in the town of Banten Girang with the intention of spreading Islam in the then Hindu-dominated area. Gunungjati eventually became the tumenggong of the Sultanate of Cirebon in 1479, succeeding his uncle and father-in-law Prince Cakrabuana who had also founded Cirebon town in 1445. In 1482 Gunungjati sent a letter to his grandfather, proclaiming independence of Cirebon from Sunda. According to the Suma Oriental, written in 1512–1515 by Tomé Pires, a Portuguese explorer, it was reported that the port of Banten still belonged to the Hindu Kingdom of Sunda, while Cirebon had been established as an Islamic state.

"First the king of Çumda (Sunda) with his great city of Dayo, the town and lands and port of Bantam (Banten), the port of Pomdam (Pontang), the port of Cheguide (Cigede), the port of Tamgaram (Tangerang), the port of Calapa (Kelapa), and the port of Chemano (Chi Manuk or Cimanuk), this is Sunda, because the river of Chi Manuk is the limit of both kingdoms. Now comes Java and we must speak of the kings within the hinterland. The land of Cheroboam (Cirebon), the land of Japura, the land of Locarj (Losari), the land of Tateguall (Tegal), the land of Camaram (Semarang), the land of Demaa (Demak)."

Although at first well received by the Sunda authorities, once news of the Portuguese-Sunda alliance in 1522 became known, Gunungjati asked the Demak Sultanate to send troops to Banten, starting the Demak-Sundanese war. It was likely that his son Hasanudin commanded this military operation in 1527, just as the Portuguese fleet was arriving of the coast at Sunda Kelapa to capture these towns. Subsequently, the Portuguese fleet that intended to establish a coastal fortress was defeated by the combined Cirebon and Demak forces.

Gunungjati and his son settled in Banten Girang, and took control of both the port of Banten and Kelapa, while Surawisesa, the king of Sunda at that time was powerless to prevent this takeover and signed a peace treaty with Demak and Cirebon in 1531. Gunungjati crowned Hasanudin as the temenggong of Banten with authority bestowed by the Sultan of Demak Trenggana who, in turn, offered Hasanudin his sister's hand in marriage. This resulted in the establishment of a new dynasty and a new kingdom. Old Banten (currently part of Serang town) was the capital of this kingdom, and was held as a province under the Sultanate of Cirebon.