Abul Hasan Abu Ishaq Kasa'i Marvazi (953 - 10th century) (Persian: ابوالحسن ابواسحاق کسایی مروزی) or Kasai is a Persian poet. He was born in Marv. He was a poet in the court of Mahmud Ghaznavi. He converted to Shia Islam. He has praised Ali ibn Abi Talib many times in his poems. All of his poems are in Persian. His poems are collected in a Diwan.