Tur Abdin (Arabic: طور عبدين; Kurdish: Tor; Latin: Turabdium; Syriac: ܛܽܘܪ ܥܰܒ݂ܕܺܝܢ or ܛܘܼܪ ܥܲܒ݂ܕܝܼܢ, Ṭūr ʿAḇdīn) is a hilly region situated in southeastern Turkey, including the eastern half of Mardin Province, and Şırnak Province west of the Tigris, on the border with Syria and famed since Late Antiquity for its Christian monasteries on the border of the Roman Empire and the Sasanian Empire. The area is a low plateau in the Anti-Taurus Mountains stretching from Mardin in the west to the Tigris in the east and delimited by the Mesopotamian plains to the south. The Tur Abdin is populated by more than 80 villages and nearly 70 monastery buildings and was mostly Syriac Orthodox with a Syriac Catholic minority until the early 20th century. The earliest surviving Christian buildings date from the 6th century.

The name "Tur Abdin" is Syriac: ܛܘܪ ܥܒܕܝܢ, lit. 'Mountain of the Servants [of God]'.‌ Tur Abdin is of great importance to the Syriac Orthodox, for whom the region used to be a monastic and cultural heartland. The Assyrian community of Tur Abdin natively refer to themselves as Sūryāyê/Sūryōyê or Sūrāyê/Sūrōyê (Syriac: ܣܘܪ̈ܝܐ), and traditionally speak a central Neo-Aramaic dialect called Turoyo.

Tur Abdin is a mountain linked to the mountain of Izla that overlooks Nisibin. The region sharing its name is home to numerous monasteries and cells, as well as around fifty villages, both large and small. Two-thirds of the residents in these villages are Syriac Christians, while the remainder consists of Muslims and Yezidis. The capital of Tur Abdin is Midyat.

The town of Midyat and the villages of Hah, Bequsyone, Dayro da-Slibo, Saleh (with the old monastery of Mor Yaqub), Iwardo (with Mor Huschabo), Anhel, Kafro, Arkah (Harabale, with Dayro Mor Malke), Beth Sbirino, Miden (Middo), Kerburan, Binkelbe with Mor Samun Zayte and Beth Zabday (Azech) were all important Syriac Orthodox settlements among with countless other villages. Hah, today called Anıtlı, has the ancient 'Idto d'Yoldath-Aloho, the Church of the Mother of God. Ignatius Aphrem I mentions the following settlements in his book: to the east of Tur Abdin are Anhil, Fifyath, and Qartmin; to the west are Bati, Habsnas, Salah, 'Urnus, 'Aynward, Kafra, Kafarze, Kafrsalta, Kafrshami, and Kandarib; to the north are Alin, Baqsyan, Hah, Hisn Kifa, Dayr Salib, Zaz, and Karburan; and to the south are Arbo, Badebe, Basibrina, Banim'im, Tamars, Hbob, Sari Awastir, 'Arban, and Meddo. The abandoned villages and those whose locations are unknown include Halih, Zabdiqa, Kafryab, and Kalasht.

Tur Abdin was referred to as the "Land of the Arameans" in the inscriptions of Assur-Bel-Kala, indicating that some territories west and northwest of Assyria were considered to be inhabited by Arameans.

Assyrian king Adad-nirari II, who came to throne in the late 10th century BCE, removed the Arameans from political power in the Kashiari mountains (Tur Abdin). In the 9th century BCE, Ashurnasirpal II described crossing the plateau of Tur Abdin (which he calls "Kashyari") on his way to attack the region of Nairi, more than once. He erected a monument in Matiate, modern-day Midyat in Tur Abdin, which remains to be found. His successor, Shalmaneser III, also crossed Tur Abdin, whom the Arameans later would again rebel against at the end of his term.

Most ancient monuments in Tur Abdin are Christian, but as attested by Ashurnasirpal II, the area has a pre-Christian history. Older names of the area indicate that the people living here worshipped Assyrian deities. Arches on the north side of the churches in Zaz and Saleh suggest pre-Christian buildings originally stood on the sites. Ancient Assyro-Babylonian religion is believed to have survived in the region until as late as the 18th century.

In 586 B.C. the prophet Ezekiel mentions the famed wine of Izlo, on the southern edge of the plateau of Tur Abdin, in his prophecy against Tyre.^{[citation needed]}