Layth ibn Tarif (Arabic: ليث بن طريف) was an 8th-century freedman commander and governor for the Abbasid Caliphate.

Wilhelm Barthold misidentified him as the son of Nasr ibn Sayyar, the last Umayyad governor of Khurasan,^[1] but according to the Kitab al-Aghani and other sources, Layth and his brother Mu'alla were the sons of a certain Tarif, a slave or client (mawla) of the Abbasid caliph al-Mansur (r. 754–775). Layth and his brother were purchased as slaves by al-Mansur and given to his heir al-Mahdi (r. 775–785), who set them free.^[1]

Layth is first mentioned as commanding an army against the king of Farghana under al-Masnur, while al-Mahdi sent him against the Iranian rebel al-Muqanna.^[1] Later al-Mahdi appointed him as governor of Sind. He was recalled during the brief reign of al-Hadi (r. 785–786), but reinstated to the post by Harun al-Rashid (r. 786–809).^[1] Either he or Layth ibn al-Fadl were governors of Dinawar in 796/7.^[1]

• Crone, Patricia (1980). Slaves on Horses: The Evolution of the Islamic Polity. Cambridge: Cambridge University Press. ISBN 0-521-52940-9.