The Baqṭ (Arabic: بقط, romanized: baqṭ) was a treaty between the Christian state of Makuria and the new Muslim rulers of Egypt in the 7th century. Lasting almost seven hundred years, it is by some measures the longest-lasting treaty in history. The name comes either from a Coptic language term for barter or a Greco-Roman term for pact.

Despite its longevity, little is known about the Baqt, and almost all information about it comes from Muslim sources.

The Baqt was signed after the 652 Arab conquest of Egypt. That year, the Hejazi general Abd Allah ibn Sa'd led an army south against the Christian kingdoms of Nubia: Makuria, Nobatia, and Alodia. Later Islamic historians state that Nubia was not worth conquering, and the expedition was to subordinate the region to Egypt. Earlier sources suggest that the Arab armies suffered a rare defeat at the second battle of Dongola and only acceded to the Baqt when they realized that conquering the region would be difficult. The treaty was negotiated between ibn Sa'd and the Makurian king Qalidurut.

There is no extant copy of the treaty they signed, and the earliest copies date to several centuries after and vary significantly. The treaty might not have been written at all, but may have been an oral agreement instead. Some sections of the Baqt are clear:

Ibn Abd al-Hakam, one of the first historians to discuss the treaty, gives two different versions of the treaty. The first has only Nubia sending slaves north, thus symbolizing its subservience to Egypt. The second version adds an obligation on the part of the Egyptians to also send goods south, including wheat and lentils, in exchange for the slaves; this would put the two nations on a more equal footing. The second version is more reliable, as it conforms with the Nubian version of the treaty and also aligns with the results of the first and second Battles of Dongola.

This treaty was unprecedented in the history of the early Muslim conquests, being more similar to the arrangements the Byzantine Empire sometimes made with its neighbours. It is also unmatched in that it largely blocked the spread of Islam and the Arabs for half a millennium. Spaulding reports that the exchange of goods was a typical diplomatic arrangement in Northeast Africa, and the Nubians would have had long experience with such agreements.

The Baqt caused some controversy among Islamic theologians; there was disagreement over whether it violated the duty to expand the dar al-Islam.

The Baqt was not always without controversy, and conflicts between the neighbours were not unheard of.