The Jalayirid Sultanate (Persian: جلایریان) was a dynasty of Turco-Mongol Jalayir origin, which ruled over modern-day Iraq and western Iran after the breakup of the Ilkhanate in the 1330s. It lasted about fifty years, until disrupted by Timur's conquests and the revolts of the Qara Qoyunlu Turkoman. After Timur's death in 1405, there was a brief attempt to re-establish the sultanate in southern Iraq and Khuzistan. The Jalayirids were finally eliminated by the Qara Qoyunlu in 1432.

The Jalayirids were Mongol and Turkicized and Turkic-speaking. They are credited with bolstering the Turkic presence in Arabic-speaking Iraq so much so that Turkic became the second-most-spoken language after Arabic. The Jalayirids were also culturally Persianate, and their era marks an important period in the evolution of Persian art, where it developed important aspects that would serve as the basis of later Persian paintings.

The history of the Sultanate of Jalayirid can be divided into four phases:

During the disintegration years of the Ilkhanate after the death of Abu Sa'id Bahadur Khan in 1335, the family of emir Ilge (Īlgā) Noyan, known as Köke (Kukā, ‘Blue’) Ilge, descendants of the Jalayirid tribe, first emerged as the inheritors of the traditional governors of the southwestern lands of the Ilkhanate. Ilge Noyan had taken over pasturelands along the River Onon in Mongolia and produced several military commanders during the Mongol era. According to the Jami' al-tawarikh written by Rashid-al-Din Hamadani, Ilge, who accompanied Hulegu on his great expedition to Western Asia in the 1250s, was among the generals who besieged the Assassins' strongholds in Qohestan in 1256. Besides, Ilge joined the expedition to Baghdad and was tasked with overseeing the rebuilding of the city after its siege in 1258. Ilge Noyan served Hülegü until the khan's death in 1265. When the Abaka khan came to the throne in 1265 and was identified as a senior emir, Ilge was in charge of the ordos ("royal headquarters"). Ilge was one of the main military leaders in conflicts with the Mamluks and Jochids, neighbors and opponents of the Ilkhanate, in Baghdad, Syria, Diyarbakir and the Caucasus.

Ilge Noyan's sons Agbuga (Āqbuqā), Tughu were also in the service of Abaga khan. Agbuga, who was promoted to mir-e mirān (commander-in-chief) by Keyhatu khan, was later assassinated by Baydu's supporters in 1295. He became the patron (murabbī) of Sadr al-Din Zanjani, Kaykhatu's grand vizier. Aq buqa was married to Qhazan khan's sister Ūljatāy Sulṭān, but after his death, his son Hussein married his father's wife and took the title of gūrgān (greregen) or royal son-in-law.

Hussein first served Oljaitu and then Abu Sa'id, and took part in the march on Gilan in 1317. He was later appointed ruler of Arran in 1313 and died in Khorasan in 1322. After his death, his son Shaykh Hasan ("Hasan Buzurg", "Hasan The Great") became the head of the family. He was both the cousin of Abu Sa'id and the nephew of Amir Choban.

After defeating his rivals, Hasan Buzurg strengthened his ties with Muhammad Khan (Pir Hussein), who ruled Anatolia at the time. He then proceeded to Tabriz where he put Muhammad on the throne and married the granddaughter of Chupan and the wife of Abu Sa'id, Dilshad Khatun. Shaykh Ḥasan was the ‘biklārī bik [beglerbeg], or amīr al-umarā’’.

For a short time in 1337–1338, Hasan Buzurg-un's authority was recognized in all parts of the Ilkhanate Empire except Khorasan, but after being expelled by Ḥasan-e Kucak and his brother Malek Ašraf in 1338–1339, he was forced to evacuate Azerbaijan and his power only held in Iraq. Hasan Buzurg died in July 1356 and was buried in Najaf. He was succeeded by his son, Shaikh Uways Jalayir.