Mashallah ibn Athari

Māshāʾallāh ibn Atharī (Persian: ماشاءالله ابن اثری یهودی; c. 740 – 815), known as Mashallah, was an 8th century Persian Jewish astrologer, astronomer, and mathematician. Originally from Khorasan, he lived in Basra (in present day Iraq) during the reigns of the Abbasid caliphs al-Manṣūr and al-Ma’mūn, and was among those who introduced astrology and astronomy to Baghdad. The bibliographer ibn al-Nadim described Mashallah "as virtuous and in his time a leader in the science of jurisprudence, i.e. the science of judgments of the stars". Mashallah served as a court astrologer for the Abbasid caliphate and wrote works on astrology in Arabic. Some Latin translations survive.

The Arabic phrase mā shā’ Allāh indicates a believer's acceptance of God's ordainment of good or ill fortune. His name is probably an Arabic rendering of the Hebrew Shiluh. Al-Nadim writes Mashallah's name as Mīshā ("Yithru" or "Jethro").

The crater Messala on the Moon is named after Mashallah.