Al-Zayadina were an Arab clan based in the Galilee. They were best known after one of their sheikhs (chiefs) Zahir al-Umar, who, through his tax farms, economic monopolies, popular support, and military strength ruled a semi-autonomous sheikhdom in northern Palestine and adjacent regions in the 18th century.

Zahir al-Umar al-Zaydani, alternatively spelled Daher al-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.