Abū Ḥātim al-Muẓaffar al-Isfazārī; (fl. late 11th – early 12th century CE) was a Persian Muslim mathematician from Khurasan. According to Ibn al-Athir and Qutb al-Din al-Shirazi, he worked in the Seljuq observatory of Isfahan. Nezami Aruzi met him in Balkh in (in present‐day Afghanistan) in 1112 or 1113.
He was a contemporary of Umar al-Khayyam and Abd al-Raḥmān al-Khāzinī. He main work is entitled Irshād dhawī al-cirfān ilā ṣinācat al-qaffān (Guiding the possessors of learning in the art of the steelyard), a relatively long text on the theory of the steelyard balance with unequal arms. His other surviving works include a summary of Euclid’s Elements, a text on geometrical measurements, and a treatise on meteorology in Persian language.