The Al-Omari Grand Mosque (Arabic: المسجد العمري الكبير), known as Jami' Al-Kabir, is a Sunni Islam mosque, located in the central district of Beirut, in Lebanon.

The building has been a place of worship including its original use as a Roman temple, and subsequently as a Roman church, before Beirut was conquered by Mamluk Egypt and it was converted into a mosque.

The Al-Omari Grand Mosque was originally a Roman temple, dedicated to the god Jupiter. The Ancient Roman influence is visible in some of the architectural elements, including the building's columns and foundations.^[1]

During the Byzantine era, the building was made into a Roman basilica that featured intricate mosaics and architectural elements of the Byzantine style.^[1] In the 7th century CE, the basilica was converted into a mosque.^[1] During the Crusader occupation of Beirut, in the 12th century, the mosque was converted into the Church of Saint John.^[1] Similar Romanesque churches with triple apses were built in Tyre and Tartus, using recuperated material such as Roman columns and capitals.^[2]

In 1291, in the Ottoman era, the Mamluks captured Beirut, and under Islamic conquest the church was again converted into a mosque. It was renamed Al-Omari Mosque after the second caliph, and became known as "Jami' Al-Kabir", or the Great Mosque. Its Mamluk-style entrance and domes and minarets were added in 1350, reflecting traces of the former church's Byzantine style.^[1][3]

Badly damaged during the Lebanese Civil War, the mosque's refurbishment was completed in 2004,^[1] under the direction of Youssef Haidar.^[4]

• Islam in Lebanon
• List of mosques in Lebanon

Media related to Al-Omari Grand Mosque at Wikimedia Commons