The Justanids or Jostanids (Persian: جستانیان) were an Iranian Zaydi Shia dynasty that ruled a part of Daylam (the mountainous district of Gilan[1]) from 791 to the late 11th century.

Two centuries later, this had become the main centre of the historical Nizari Ismailis or Assassins (Hashshashin), as they are known in the west.

[3] This refers to a period in which indigenous Daylamite and Kurdish principalities took power in northwest Persia after two to three centuries of Arab rule.

In the 10th century, they were eclipsed by the Daylamite dynasty of Sallarids in Tarom (modern Iranian province of Zanjan).

Nevertheless, the Justanids were tied by marriage with the Sallarids and preserved their seat of Rudbar in the highlands of Daylam.