Naṣr al-Thamalī (Arabic: نصر الثملي) was an Abbasid military commander and governor (wali or amir) of Tarsus and the borderlands with the Byzantine Empire in Cilicia (al-thughur al-Shamiya).
As his nisba shows, he was a former ghulam of Thamal al-Dulafi, who was the governor of Tarsus and the borderlands with the Byzantine Empire in Cilicia in c. 923–932.
In winter of that year (December 941/January 942) he took advantage of a Byzantine expedition against Aleppo to raid Byzantine territory himself, returning with much plunder and prisoners, including senior Byzantine commanders.
[3] In October 946 he supervised the prisoner exchange with the Byzantines—headed by John the Mystikos and the magistros Kosmas — on the River Lamos on behalf of the Hamdanid emir Sayf al-Dawla, who had in the meantime become the new overlord of the Cilician marches.
2,482 Muslims were exchanged for an equal number of Byzantine captives; as the Byzantines held 230 prisoners more, they had to be ransomed with money.