The Nezamiyeh (Turkish: Nizamiye Medresesi, Persian: نظامیه, Arabic: النظامیة) are a group of the medieval institutions of higher education established by Khwaja Nizam al-Mulk in the eleventh century in Iran. The name nizamiyyah derives from his name. Founded at the beginning of the Seljuk empire, these Sunni Islam theological schools are considered to be the model of madrasahs, or Islamic religious schools.
Nizamiyyah institutes were the first well organized institutions of higher learning in the Muslim world. The quality of education was the highest in the Islamic world, and they were even renowned in Europe. They were supported financially, politically, and spiritually by the royal establishment and the elite class. Some scholars have suggested that the establishment of the Nizamiyya madrasas was in fact an attempt to thwart the growing influence of another group of Muslims, the Ismailis, in the region. Indeed, Nizam al-Mulk devoted a significant section in his famous Books of Politics (Siyāsatnāma) to refuting the Ismaili doctrines.
The most famous and celebrated of all the nizamiyyah schools was Al-Nizamiyya of Baghdad (established 1065), where Khwaja Nizam al-Mulk appointed the distinguished philosopher and theologian, al-Ghazali, as a professor. Persian poet Sa'di was a student of the Baghdad Nizamiyyah. Other nizamiyyah schools were located in Nishapur, Amol, Balkh, Herat and Isfahan.
Nizam ul-Mulk was finally assassinated en route from Isfahan to Baghdad in 1092 CE. According to several books, he was assassinated by a member of Hashshashin, a group of the Ismaili sect of Shi'a Islam.
According to Mughatil ibn Bakri, a staff member of the Al-Nizamiyya of Baghdad, he alleges that Nizam al-Mulk converted to Shia Islam after a Sunni-Shia debate held on the orders of Sultan Malik Shah I, who also converted to Shia'ism. But it is thereafter that they were both assassinated. This narration is disputed, however, by most historians and Sunni scholars.
- Ed(s). "al- Niẓāmiyya , al- Madrasa." Encyclopaedia of Islam, Second Edition. Edited by: P. Bearman , Th. Bianquis , C.E. Bosworth , E. van Donzel and W.P. Heinrichs. Brill, 2010, retrieved 20(03/2010)
- Virani, Shafique N. The Ismailis in the Middle Ages: A History of Survival, A Search for Salvation (New York: Oxford University Press, 2007), 73.
- Mughatil ibn Bakri, In search of Truth in Baghdad (در جستجوی حق در بغداد), also appearing under the title "راهي به سوي حقيقت", ISBN 964-93287-8-5, p.134-136. Link to item in publisher's catalog: 
- Higher education in Iran
- Academy of Gundishapur
- School of Nisibis
- List of universities in Iran
- List of Iranian scientists from the pre-modern era.
- Modern Iranian scientists and engineers
- List of Iranian Research Centers
- House of Wisdom, another establishment in Baghdad