Jacob Qirqisani (c. 890 – c. 960) (Arabic: ابو یوسف یعقوب القرقسانی ʾAbū Yūsuf Yaʿqūb al-Qirqisānī, Hebrew: יעקב בן יצחק הקרקסאני Yaʿqov ben Yiṣḥaq haṢerqesi) was a Karaite dogmatist and exegete who flourished in the first half of the tenth century. His origins are unknown. His patronym "Isaac" is the addition of a later copyist, and may reflect no more than the genealogy of the biblical patriarchs, while his surname has been taken as referring to either ancient Circesium (al-Busayra) in eastern Syria or Karkasān, near Baghdad. He seems to have traveled throughout the Middle East, visiting the centers of Islamic learning, in which he was well-versed.