Najm ad-Dīn Abū Ḥafṣ 'Umar ibn Muḥammad an-Nasafī (Arabic: نجم الدين أبو حفص عمر بن محمد النسفي; 1067–1142) was a Muslim jurist, theologian, mufassir, muhaddith and historian.
A Persian scholar born in present-day Uzbekistan, he wrote mostly in Arabic.
He authored around 100 books in Hanafi jurisprudence, theology, Quran exegesis, Hadith and history.
He studied under prominent scholars such as Fakhr al-Islam al-Bazdawi, Abu al-Yusr al-Bazdawi, and Abu al-Mu'in al-Nasafi.
Burhan al-Din al-Marghinani, the author of Al-Hidayah, was his most famous student.