Abu Hafsa Yazid (Arabic: ابو حفصة يزيد Abū Ḥafṣah Yazīd) was a mawla, or servant, of the Umayyad Caliph Marwan ibn al-Hakkam (r. 684–685). Yazid's full name is not known; Abu Hafsa means "father of Hafsa" (see Arabic name).
Abu Hafsa Yazid's origins are unclear; he may have been either Persian or Jewish. He may have been taken prisoner as a youth in the capture of Istakhr in 659 CE, and later sold to the Caliph. He was freed on the day of the assassination of Uthman ibn Affan. Sources vary as to whether Abu Hafsa Yazid converted to Islam or retained his Jewish faith.
Abu Hafsa Yazid is sometimes described as court physician to the CaliphUmar I around the year 643 CE, however this may be an error based on writings by later Arab historians, as he is not called a physician in the earliest texts.