The Ouaddai Empire (1635–1912) (Also Wadai Empire) was originally a non-Muslim kingdom, located to the east of Lake Chad in present-day Chad. It emerged in the sixteenth century as an offshoot of the Sultanate of Darfur (in present-day Sudan) to the northeast of the Kingdom of Baguirmi.

In 1635, the Maba and other small groups in the region rallied to the Islamic banner of Abd al-Karim^{[disambiguation needed ]}, who led an invasion from the east and overthrew the ruling Tunjur group. Abd al-Karim became the first Kolak or Sultan of a dynasty that lasted until the arrival of the French. During much of the 18th century, Ouaddai resisted reincorporation into Darfur.

In about 1800, during the reign of Sabun, the sultanate of Ouaddai began to expand its power as it profited considerably from its strategic position astride the trans-Saharan trade routes. A new trade route north—via Ennedi, Kufra and Benghazi--was discovered, and Sabun outfitted royal caravans to take advantage of it. He began minting his own coinage and imported chain mail, firearms, and military advisers from North Africa. Sabun's successors were less able than he, and Darfur took advantage of a disputed political succession in 1838 to put its own candidate in power in Wara, the capital of Ouaddai. This tactic backfired, however, when Darfur's choice, Muhammad Sharif, rejected Darfur's meddling and asserted his own authority. In doing so, he gained acceptance from Ouaddai's various factions and went on to become Ouaddai's ablest ruler. Sharif conducted military campaigns as far west as Bornu and eventually established Ouaddai's hegemony over Baguirmi and kingdoms as far away as the Chari River. In Mecca, Sharif had met the founder of the Senussi Islamic brotherhood, a movement that was strong among the inhabitants of Cyrenaica (in present-day Libya) and that was to become a dominant political force and source of resistance to French colonization.