Omar Ali Saifuddien Mosque (Malay: Masjid Omar Ali Saifuddien, Jawi: مسجد عمر علي سيف الدين‎) is a mosque in Bandar Seri Begawan, the capital of Brunei. It is one of the country's two masjid negara or national mosques (the other Jame' Asr Hassanil Bolkiah Mosque), as well as a national landmark. It is one of the largest and oldest mosques in the country and is named after Omar Ali Saifuddien III (1914–1986), the 28th Sultan of Brunei and the father of the current monarch Sultan Hassanal Bolkiah. The mosque serves as a symbol of the Islamic faith in Brunei.