The Great Mosque of Gaza also known as the Great Omari Mosque is the largest and oldest mosque in the Gaza Strip, located in Gaza's old city.

Believed to stand on the site of an ancient Philistine temple, the site was used by the Byzantines to erect a church in the 5th century, but after the Muslim conquest in the 7th century, it was transformed into a mosque. Described as "beautiful" by an Arab geographer in the 10th century, the Great Mosque's minaret was toppled in an earthquake in 1033. In 1149, the Crusaders built a cathedral dedicated to John the Baptist, but it was mostly destroyed by the Ayyubids in 1187, and then rebuilt as a mosque by the Mamluks in the early 13th century. It was destroyed by the Mongols in 1260, then soon restored only for it to be destroyed by an earthquake at the end of the century.

The Great Mosque was finally rebuilt by the Ottomans roughly 300 years later. Severely damaged after British bombardment during World War I, the mosque was restored in 1925 by the Supreme Muslim Council. The Great Mosque is still active today, serving as a Friday mosque.