Ömerli (Arabic: معسرتي, Kurdish: Masertê,[2] Syriac: ܡܥܨܪܬܗ, romanized: Maʿsarteh)[3][nb 1] is a municipality and district of Mardin Province, Turkey.

[8] Maʿsarteh (today called Ömerli) is identified as the town of Madaranzu in Bit-Zamani, which was conquered by Ashurnasirpal II, King of Assyria, in 879 BC.

[8] It was likely captured by a Sasanian army in 573 at the time of the siege of Dara, during the Roman-Sasanian War of 572-591, but was retaken and the fort was restored by the Roman commanders Theodore and Andrew in 587.

[12] Maʿsarteh was inhabited by 300 Syriac Orthodox Assyrians in 1914 and served by the church of Mar Gewergis, according to the list presented to the Paris Peace Conference by the Assyro-Chaldean delegation.

[13] Amidst the Sayfo, in 1915, the village's owner Huseyin Bakkero murdered 80 Assyrians at his house after assuring them of their safety and threw their bodies into wells.