Qabus ibn Wushmagir;
(full name: Abol-Hasan Qābūs ibn Wušmagīr ibn Ziyar Sams al-maʿālī, ابوالحسن قابوس بن وشمگیر بن زیار, شمس المعالی; (died 1012) (r. 977–981; 997–1012) was the Ziyarid ruler of Gurgan and Tabaristan in medieval Iran. His father was Vushmgir and his mother was a daughter of the Bavandi Ispahbad Sharwin II.
Upon Vushmgir’s death in 967, his eldest son Bisutun marched to the capital Gurgan to take control of the Ziyarid state. A Samanid army that had arrived shortly before Vushmgir’s death for a joint campaign against the Buyids, however, threw its support behind Qabus. When Bisutun gained the assistance of the Buyid Rukn al-Dawla the Samanid army left for Khurasan. Qabus found a new ally in al-Hasan ibn al-Fairuzan, who ruled in Semnan, but Bisutun occupied both Gurgan and Semnan, forcing Qabus to give up his claims as his father’s successor.