Fadak (Arabic: فدك‎) was a garden oasis in Khaybar, a tract of land in northern Arabia; it is now part of Saudi Arabia. Situated approximately thirty miles from Medina, Fadak was known for its water-wells, dates, and handicrafts. When the Muslims defeated the people of Khaybar at the Battle of Khaybar; the oasis of Fadak was part of the booty given to the Prophet Muhammad. Much before his death, he bequeathed it to his daughter, Fatimah. Even so, it became the object of dispute between Fatimah and the caliph Abu Bakr.

In the 7th century, the Khaybar oasis was inhabited by Arab Jews, who pioneered the cultivation of the oasis and made their living growing date palm trees, as well as through commerce and craftsmanship, accumulating considerable wealth. Some objects found by the Muslims in a redoubt at Khaybar — a siege-engine, 20 bales of Yemenite cloth, and 500 cloaks — point out to an intense trade carried out by the Jews.

The oasis was divided into three regions: al-Natat, al-Shiqq الشِّق, and al-Katiba الكتيبة, probably separated by natural diversions, such as the desert, lava drifts, and swamps. Each of these regions contained several fortresses or redoubts containing homes, storehouses and stables. Each fortress was occupied by a clan and surrounded by cultivated fields and palm-groves. In order to improve their defensive capabilities, the fortresses were raised up on hills or basalt rocks.