The Grand Mosalla of Tehran, officially the Imam Khomeini Mosalla of Tehran, is a partially completed Friday mosque (jāmeh) and associated community complex, located near Abbas Abad in the city of Tehran, in the province of Tehran, Iran. The mosque is used for hosting weekly Friday prayer (jāmeh), as well as cultural, political, educational, worship activities, including book fairs, exhibitions, and religious ceremonies.
The Persian-Islamic style mosque has been under construction since the 1990s. Upon completion, the mosque will have the world’s biggest iwan. If one distant day completed, the mosque will surpass the Masjid al-Haram in Mecca, the world’s largest mosque.
As of April 2025, more than 30 years after the design was finalized, the Grand Mosalla remained under construction, though finished sections of the building were in use. In 2017, the Financial Tribune called the condition of the project “dismal” and “unacceptable”, and Governor General of Tehran Province Hussein Hashemi urged Tehran City Council to prioritize the mosque’s completion.
The mosque complex is also used as a community center and a venue for local and national events, including the Tehran International Book Fair, International Holy Quran Exhibition, International Exhibition of Investment Opportunities in Iran’s Mines and Mining Industries, International Handicrafts Exhibition, and the Tehran Game Exhibition, among other events.
The Grand Mosalla Mosque is served by the Mosalla Imam Khomeini Metro Station, a Tehran Metro station located in the Grand Mosalla, next to the Qasem Soleimani Expressway. It also has a bus rapid transit station in Line 5: Science & Tech Terminal to Argentina Square Beihaghi Terminal.
