Zahir al-Umar al-Zaydani, alternatively spelled Dhaher el-Omar or Dahir al-Umar, was an Arab ruler of northern Palestine in the mid-18th century, while the region was part of the Ottoman Empire. For much of his reign, starting in the 1730s, his domain mainly consisted of the Galilee, with successive headquarters in Tiberias, Deir Hanna and finally Acre, in 1750. He fortified Acre, and the city became the center of the cotton trade between Palestine and Europe. In the mid-1760s, he reestablished the port town of Haifa nearby.