The Encyclopaedia Islamica is an encyclopedia on Islamic and Iranian studies published by Brill, comprising a projected 16-volume translation of selected articles from the new Persian Dā'erat-ol-Ma'āref-e Bozorg-e Eslāmi (Persian: دائرةالمعارف بزرگ اسلامی, "The Great Islamic Encyclopaedia"), supplemented by additional articles written in English by scholars affiliated with the Institute of Ismaili Studies.

[1][2] The Persian-language project has been led by Kazem Mousavi-Bojnourdi since 1983, when the Center for the Great Islamic Encyclopedia was established in Teheran for the purpose of constituting a scientific committee to oversee its creation.

[1][2][3] As of 2016, the encyclopedia is at the ninth letter of the Persian alphabet and its 22nd completed volume.

[4] Brill's Encyclopaedia Islamica, which is edited by Farhad Daftary and Wilferd Madelung, is currently at its fifth volume.

[6] It is intended for advanced graduate students and scholars who require meticulous documentation.