Abul Hassan Ali Ibn Usman al-Jullabi al-Hajweri al-Ghaznawi or Abul Hassan Ali Hajweri (Arabic: علی بن عثمان الجلابی الهجویری الغزنوی ) (sometimes spelled Hujwiri), also known as Data Ganj Bakhsh (Persian/Urdu: داتا گنج بخش ) or Data Sahib, was a Persian Sufi and scholar during the 11th century. He significantly contributed to the spreading of Islam in South Asia.
He was born in Ghazna (in present day Afghanistan) in the beginning of Ghaznavids period and died in Lahore (in present day Punjab, Pakistan) in 1077 CE. His most famous work is Kashf al-Mahjub ("Unveiling the Veiled") written in Persian language. The work debates Sufi doctrines of the past. Hujwiri said that individuals should not claim to have attained "marifat" or gnosis because it meant that one was prideful. True understanding of God should be a silent understanding.